Abstract:
A device for attachment to both porous and non-porous wall surfaces includes a suction cup having an elastomeric core and an elastomeric outer layer that is substantially softer than the inner layer. The outer layer includes material that fills pores within a porous surface against which the suction cup is held. The inner layer prevents tearing of the suction cup and causes a partial vacuum to be formed as the suction cup attempts to return to its original shape following depression against a wall surface.

Description:
RELATED APPLICATIONS 
       [0001]    Not Applicable 
       FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not Applicable 
       BACKGROUND OF THE INVENTION 
       [0003]    1. Field of the Invention 
         [0004]    This invention relates to a suction cup apparatus for attachment to a wall surface, and, more particularly to such an apparatus capable of being securely attached both to porous and nonporous surfaces. 
         [0005]    2. Summary of the Background Information 
         [0006]    A number of devices are available for attaching objects to walls using suction cups. In the simplest form of such a device, the central portions of one or more suction cups are directly attached to a housing or frame of the device. Each of the suction cups, which are composed of an elastomeric material, includes a concave surface held against the wall. For example, the elastomeric suction cups are pressed into place on the rigid frame of the device, or an elastomeric material may be molded over a rigid plastic frame to form one or more suction cups extending outward from the frame. When the device is pressed toward the wall, a portion of the air held between the concave surface and the wall is pushed outward, past the periphery of each suction cup. Then, after the device is released, as each suction cup tries to return to its original shape while the shape of the suction cup extending to its periphery blocks the inward movement of air, a partial vacuum is formed between the concave surface and the wall, holding the device in place on the wall. 
         [0007]    In another type of suction cup device, the central portion of a suction cup is attached to an actuator, while the periphery of the suction cup is held by a ring forming part of the device. First, the periphery of the suction cup is held against the wall with the actuator holding the central portion of the suction cup close to the wall. Then, as the periphery of the suction cup remains against the wall, the actuator is moved so that the central portion of the suction cup is moved away from the wall, increasing the volume of the space between the concave surface of the suction cup and the wall to form a partial vacuum within this space, holding the device in place on the wall. Again, the shape of the suction cup extending to its periphery blocks the inward flow of air. 
         [0008]    Both types of suction cup generally work well on hard and smooth wall surfaces, such as ceramic tile, glass, stainless steel, or painted metal. However, when the suction cup is attached to a wall having a porous surface, such as painted gypsum wallboard, the porosity of the wall surface allows a slow leakage of air past the periphery of the suction cup into the space between the concave surface of the suction cup and the wall. This leakage of air reduces the level of partial vacuum within this space, so that the device falls off the wall, typically within a few hours to two weeks after its installation on the wall. 
       SUMMARY OF THE INVENTION 
       [0009]    According to one aspect of the invention, a suction cup comprising a core and an outer layer is provided. The core is composed of a first elastomer, and the outer layer is composed of a second elastomer, which is substantially softer than the first elastomer. The core forms a central portion, a disk-shaped portion, and an annular peripheral portion. The disk-shaped has a concave outward-facing surface extending radially from the central portion to the annular peripheral portion. The outer layer covers at least an outward-facing surface of the annular peripheral portion. 
         [0010]    The outer layer may additionally cover surfaces of the disk-shaped portion and of the central portion. Preferably, the first elastomer has a hardness in the range of Shore A 50 to Shore A 70, while the second elastomer has a hardness in the range of Shore A 10 to Shore A 20. The outer layer preferably has a thickness in the range of 0.8 mm to 1.8 mm. Preferably, the first and second elastomers are thermoplastic elastomers, silicone rubbers, or urethane elastomers. 
         [0011]    The relatively high level of hardness of the first elastomer is needed to prevent tearing and to provide sufficient force to form a partial vacuum between the concave surface and a surface to which the suction cup is attached, such as a wall. The relatively low level of hardness of the second elastomer is needed to provide for reliable attachment to a porous surface, such as a gypsum wallboard, with the elastomeric material moving into pores within the porous surface. 
         [0012]    According to another aspect of the invention, apparatus for attachment to a wall, comprising a housing and a suction cup as described above, is provided, with the suction cup being attached to the housing. The central portion of the core may be attached to the housing, with the peripheral portion being inwardly deflectable. Alternately, the apparatus additionally includes an actuator attaching the central portion of the suction cup to the housing. The actuator is mounted on the housing to be moved between a released position and an engaged position, with the central portion being moved in an inward direction as the actuator is moved from the released position to the engaged position. The housing includes a ring preventing movement of the peripheral portion of the core as the actuator is moved from the released position to the engaged position. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is a rear elevation of a device built in accordance with a first embodiment of the invention; 
           [0014]      FIG. 2  is a fragmentary cross-sectional side elevation of the device of  FIG. 1 , taken as indicated by section lines  2 - 2  therein, showing a suction cup therein; 
           [0015]      FIG. 3 , is a fragmentary side elevation of the device of  FIG. 1 , shown as attached to a wall surface; 
           [0016]      FIG. 4  is a fragmentary side elevation of an alternate suction cup for use in the device of  FIG. 1 ; 
           [0017]      FIG. 5  is a perspective view of a device built in accordance with a second embodiment of the invention; 
           [0018]      FIG. 6  is a fragmentary cross-sectional plan view of a housing and a bracket in the device of  FIG. 5 , taken as indicated by section lines  2 - 2  therein; 
           [0019]      FIG. 7  is a perspective view of the bracket within the appliance holder of  FIG. 5 ; 
           [0020]      FIG. 8  is a perspective view of an alternative bracket for attachment to the housing within the appliance holder of  FIG. 5 ; 
           [0021]      FIG. 9  is a cross-sectional perspective view of the appliance holder of  FIG. 5  with a pivoted actuator therein in a released position, taken as indicated by section lines  9 - 9  in  FIG. 5 ; and 
           [0022]      FIG. 10  is a cross-sectional perspective view of the appliance holder of  FIG. 1  with the pivoted actuator therein in an actuated position, taken as indicated by section lines  9 - 9  in  FIG. 5 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0023]      FIG. 1  is a rear elevation of an device  10  for attachment to a wall built in accordance with a first embodiment of the invention to include a housing  12  and four suction cups  14  for attaching the device  10  to a wall surface  16  (shown in  FIG. 3 .) 
         [0024]      FIG. 2  is a fragmentary cross-sectional side elevation of the device  10 , taken as indicated by section lines  2 - 2  in  FIG. 1  to show one of the suction cups  14 , which is attached to the housing  12  by being pushed onto a pin  18  forming part of the housing  12 . For example, the housing  12  is formed as a picture holder having an opening  20  in a front surface  22 . In accordance with the invention, the suction cup  14  comprises a core  24 , composed of a relatively tough elastomeric material, and an outer layer  26 , composed of a relatively soft elastomeric material. The core  24  forms a central portion  27 , a disk-shaped portion  28 , and an annular peripheral portion  29 . The disk-shaped portion  28  has an outward-facing concave surface  30  extending radially, in the directions of arrows  32 , from the central portion  27  to the annular peripheral portion  29 . The outer layer  26  may be formed by overmolding. 
         [0025]      FIG. 3  is a fragmentary cross-sectional side elevation of the device  10 , again taken as indicated by section lines  2 - 2 , showing the suction cup  14  as it is deflected by engagement with the wall surface  16 . The device  10  is attached to the wall surface  16  by pressing the device  10  in the outward direction of arrow  36 , toward the wall surface  16 , with the suction cups  14  held against the wall surface  16 , so that some of the air held within a space  38  between the concave surface  30  and the wall surface  16  is pushed radially, in the directions of arrows  32 . Then, after the device  10  is released, each of the suction cups  10  attempts to return to its original shape, as shown in  FIG. 2 , enlarging the space  38  so that a partial vacuum is formed within this space  38 , holding the annular peripheral portion  29  of the suction cup  14  against the wall surface  16 . It is noted that, as air moves radially out, in the directions of arrows  32  along an outer surface  39  adjacent the annular peripheral portion  29 , resulting forces, acting on the annular peripheral portion  29  in the directions of arrows  32  form torques in the directions of arrows  40 , which move the annular peripheral portion  29  away from the wall surface  16 , allowing the airflow to continue. On the other hand, when air attempts to move inward, opposite the directions of arrows  30  along the outer surface  39 , resulting forces, acting on the annular peripheral portion  29  opposite the directions of arrows  40 , push the annular peripheral portion  29  toward the wall surface  16 , preventing the movement of air into the space  38 . 
         [0026]    The outer layer  26  provides the suction cup  14  with an outer surface  40  that is soft enough to move into pores within the wall surface  16 , as the peripheral portion  34  is held against the wall surface  16 , blocking a movement of air through these pores when the suction cup  14  is attached to a porous wall surface  16 . The suction cup  14  is thus rendered capable of attaching the housing  12  to a porous wall surface, such as a gypsum wallboard surface, for a long period of time. On the other hand, a conventional suction cup (not shown), composed of a relatively tough elastomeric material without the softer outer layer  26 , can only hold an object in place on such a porous surface for a few hours, due to an inward migration of air, opposite the directions of arrow  30 , through pores within the wall surface  13 , reducing the partial vacuum within the space  38 . 
         [0027]    The relatively tough elastomeric core  24  is needed to provide the suction cup  14  with sufficient rigidity to prevent tearing of the suction cup  14 , which could occur, particularly during the removal of the suction cup  14  from the wall surface  16 , if the suction cup  14  were composed entirely of the relatively soft material forming the outer layer  26 . Furthermore, the relatively tough elastomeric core  24  is needed to provide the suction cup  14  with sufficient rigidity to form the partial vacuum within the space  38 , needed to hold the suction cup  14  in place on the wall surface  16  during an attempt of the suction cup  14  to return to its original shape, as shown in  FIG. 2 . 
         [0028]    Preferably, the elastomeric core  24  is composed of an elastomeric material with a hardness within the range of Shore A 50 to Shore A 70, while the outer layer  26  is composed of an elastic material having a hardness in the range of Shore A 10 to Shore A 20. Preferably, the outer layer  26  has a thickness within a range of 0.8 mm (0.03 in.) to 1.8 mm (0.07 in.). For example, the elastomeric core  24  and the outer layer  26  are composed of TPEs (thermoplastic elastomers), silicone rubbers, or urethane elastomers. 
         [0029]      FIG. 4  is a fragmentary cross-sectional elevation of an alternative suction cup  50 , having a relatively soft outer elastomeric layer  52  extending along the contact surface  52  of the peripheral portion  54  without extending over all other surfaces  56  of the core  58 . Since this contact surface  52  is the only portion of the alternative suction cup  50  that is held against the wall surface  16 , the presence of the soft elastomeric layer  52  on this surface  52  provides the advantage of migration of the softer elastomeric material into pores within the wall surface  16  without a need to cover the other surfaces  56  of the core  58  with the layer  52 . 
         [0030]      FIG. 5  is a perspective view of an device  110 , built in accordance with a second embodiment of the invention, shown as seen from below, in front, and from the left. The device  110  includes a housing  112 , a suction cup  114  extending along a rear side  116  of the housing, a pivoted actuator  118 , and a bracket  120 . When the suction cup  114  is held against a wall surface (not shown), the pivoted actuator  118  is moved in a first direction, indicated by arrow  122 , to cause the suction cup  114  to be held against the wall surface, and opposite the first direction to cause the suction cup  114  to be released from the wall surface. The bracket  120  includes a plate  124 , extending forward, in the direction of arrow  126 , having a pair of apertures  128  for holding a pair of electrical appliances (not shown). Each of the apertures  124  includes a rounded portion  130 , which is sized to extend around a handle of an electrical appliance (not shown), and a slot  132 , extending forward to an edge  134  of the plate  124 . Each of the slots  132  is provided so that an electrical appliance may be placed within the aperture  124  with its power cord extending downward to an electrical outlet. 
         [0031]      FIG. 6  is a fragmentary cross-sectional plan view of the housing  112  and the bracket  120 , taken as indicated by section lines  6 - 6  in  FIG. 5  to show a housing track  136  forming a portion of the housing  112  and a bracket track  138  forming a portion of the bracket  120 . The housing track  134  extends along a front side  140  of the housing  112  in a first direction, indicated by arrow  142 , which is parallel to the rear side  116  of the housing  112 , allowing the device  110  to be attached to a vertical wall surface with the first direction facing downward. The bracket track  138  extends along the housing track  134 , also in the first direction, indicated by arrow  142  with a dovetail arrangement  144  being provided to maintain alignment of the bracket track  138  with the housing track  136 . The plate  124  extends perpendicular to the direction of the bracket track  138 , so that, when the device  110  is aligned on a wall with the first direction facing downward, the plate  124  will extend horizontally, in an orientation appropriate for holding electrical appliances within the apertures  128 . 
         [0032]      FIG. 7  is a perspective view of the bracket  120 , shown as removed from the housing  112 . The bracket track  138  extends in the downward direction of arrow  142  between a closed upper end  146  and an open lower end  148 , which is placed over the upper end of the housing track  136  before moving the bracket  120  downward, with the bracket track  138  engaging the housing track  134 . 
         [0033]      FIG. 8  is a perspective view of an alternative bracket  150  for attachment to the housing  112 , which includes the bracket track  138  as described above in reference to  FIGS. 6 and 7 , allowing the alternative bracket  150  to be attached to the housing  112  in place of the bracket  120 . The alternative bracket  150  includes, for example, a larger opening  152  to hold a cup or a larger appliance handle. A single housing  112  may be provided with a plurality of different brackets  120 ,  150  so that various functions can be performed. Since each of the different brackets  120 ,  150  can be placed on the housing  112  from above to be held in place on the housing  112  by gravity, the changing of brackets on a single housing  112  is easily performed, even without removing the housing  112  from a wall to which it is attached. 
         [0034]      FIGS. 9 and 10  are cross-sectional perspective views of the device  110 , taken as indicated by section lines  9 - 9  in  FIG. 6 , with the pivoted actuator  118  being shown in a released position in  FIG. 9  and in an actuated position in  FIG. 10 . The pivoted actuator  118  is pivotally mounted by a pin  156  extending through a shaft  158 , which in turn extends through a central hole  160  in a front side  162  of the housing  112 . The shaft  158  includes a flange  164 , which is disposed within a central portion  166  of a core  167  within the suction cup  114 , causing this central portion  166  to move with the shaft  158 . The core  167  is composed of an elastomeric material molded over the flange  164 . The shaft  158  holds the suction cup  114  in a position extending across and within a rear opening  168  within a rear side  170  of the housing  112 . The housing  112  additionally includes a sidewall  172  extending forward at each side of the pivoted actuator  118 , holding the pivoted actuator  118  in place so that it can pivot only about the shaft  156 . 
         [0035]    The process of attaching the appliance holder to a surface  174  of a wall  176  begins with the pivoted actuator in the released position indicated in  FIG. 9 . As the device  110  is held against the surface  174 , an annular peripheral portion  177  of the suction cup  114  is held against a ring-shaped peripheral surface  178  of the housing  112 , which extends long the rear side  170  around the rear opening  168 . Then, the pivoted actuator  118  is moved in the direction of arrow  122  into the actuated position as shown in  FIG. 10 . The pivoted actuator  118  has a cam surface  180 , with a first portion  182  held against a central surface  184  of the housing  112  with the pivoted actuator  118  in the released position of  FIG. 9 , and with a second portion  186  held against the central surface  184  with the pivoted actuator  118  in the actuated position of  FIG. 10 . Since the first portion  182  is closer to the pivot pin than the second portion  186 , moving the pivoted actuator  118  from the released position of  FIG. 9  to the actuated position of  FIG. 10  moves the shaft  158  in the forward direction indicated by arrow  188 , so that a space  190  between the wall surface  174  and the suction cup  114  is enlarged, forming a partial vacuum within the space  190  so that the device  110  is held in place against the wall surface  174 . Deflection occurs within a disk-shaped portion  192  of the core  167  of the suction cup  114 . 
         [0036]    In accordance with the invention, the suction cup  114  additionally includes an outer layer  194  of an elastomeric material that is substantially softer than the material forming the core  167 . This outer layer  194  may cover the entire core  167 , or it may be cover only the portion of the suction cup  114  that is brought into engagement with the surface  174  of the wall  176 . Other aspects of the materials forming the core  167  and the outer layer  194  are as described above in reference to  FIGS. 2-5 . 
         [0037]    While preferred embodiments of the present invention have been particularly described herein, it is understood that various changes from this description can be made without departing from the spirit and scope of the invention, as described in the appended claims.