Patent Publication Number: US-8118336-B2

Title: Door stop

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims benefit of Provisional Appln. 61/059,779, filed Jun. 8, 2008 under 35 U.S.C. §119(e). 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to door stops, and in particular to a door stop with a extended flange deflectably mounted to engage a door to be stopped. 
     2. Description of the Related Art 
     A number of door stops have been described in the art, each with some advantage in terms of manufacturing or footprint or portability or ease of use without requiring a user to bend down and manually move a device in place every time a door is opened. For example, spring action door stops described in U.S. Pat. No. 4,044,424 to A. Sasgen (hereinafter Sasgen) and U.S. Pat. No. 5,331,719 to T. Hum (hereinafter Hum) work by applying pressure on the underside of a door when the door is positioned over the device. While suitable for many purposes, these doorstops suffer various deficiencies. For example, Sasgen involves rather precise knowledge of the distance between the bottom of the door and the floor, and different devices are suggested for different distances. In Hum, a high friction material is required on both an upper surface to engage the underside of a door and on a lower surface to prevent slippage on the floor. Since doors and floor materials can differ widely, from metal to wood to carpet to plastic, for example, different high friction material combinations are needed to engage both boor and floor. Furthermore, in Hum a user must depress the doorstop, such as with the user&#39;s foot, to position the door over the doorstop. Such maneuvers are sometimes difficult and awkward. 
     SUMMARY OF THE INVENTION 
     In one embodiment, a doorstop for holding a door in an open position includes a flange connected to a floor contacting portion. The flange is deflectable under transverse pressure. During operation, a door-engaging end portion of the flange contacts a vertical face of a door to keep the door in an open position. Upon deflection, the door-engaging end portion drops below the vertical face of the door to allow the door to close. 
     In another embodiment, a doorstop for holding a door in an open position includes a spring member and a flange. The spring member includes an arc-shaped portion having a rest curvature and a floor contacting end portion. The arc-shaped portion is deflectable to an arc with less curvature under transverse pressure and returns to the rest curvature upon removal of the transverse pressure. The flange includes a door-engaging end portion and a different attached portion that is attached to the arc-shaped portion of the spring member. The flange is substantively tangent to the arc-shaped portion of the spring member along the attached portion. The door-engaging end portion of the flange contacts a vertical face of a door to keep the door in an open position. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings and in which like reference numerals refer to similar elements and in which: 
         FIG. 1  is a perspective drawing that illustrates a doorstop, according to an embodiment; 
         FIG. 2  is a plan view that illustrates the doorstop, according to the same embodiment; 
         FIG. 3  is an elevation view that illustrates the doorstop, according to the same embodiment; 
         FIG. 4  is a diagram that illustrates the operation of the doorstop as a door passes over, according to the same embodiment; 
         FIG. 5  is an elevation view that illustrates a doorstop, according to a different embodiment; 
         FIG. 6  is an elevation view that illustrates a doorstop, according to another different embodiment; and 
         FIG. 7  is an elevation view that illustrates a doorstop, according to still another different embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     An apparatus is described for operating as a doorstop. In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to avoid unnecessarily obscuring the present invention. 
       FIG. 1  is a perspective drawing that illustrates a doorstop  100 , according to an embodiment. The doorstop  100  is depicted deployed on a horizontal floor indicated in  FIG. 1  by diagonal lines; however, the floor is not part of the doorstop  100 . 
     The doorstop includes a spring member  110  and a flange  120 . The spring member  110  includes an arc-shaped portion  112  having a rest curvature and a floor contacting end portion  114  that is flat. The flange  120  includes a door-engaging end portion adjacent to door-engaging end  124  and a different attached portion  122  that is attached to the arc-shaped portion  112  of the spring member. The flange  120  is substantively tangent to the arc-shaped portion  112  along the attached portion  122 . In this embodiment, the flange  120  includes a floor contacting end portion adjacent to floor contacting end  126  opposite the door-engaging end  124 . In the illustrated embodiment, the flange  120  is also arc-shaped in the floor contacting end portion. An advantage of this embodiment is that the footprint of the door stop  100  is reduced compared to a flange that is straight from the attached portion to the floor contacting end  126 . Another advantage is that the flange  120  with an arc-shaped floor contacting end portion contributes to returning the door stop to a rest configuration, described below. 
     Any method may be used to attach the flange  120  to the spring member  110 , including the use of fasteners, glue, solder, welding, and manufacture as an integrate unit of the same material. In an example embodiment, flange and spring member are attached with three spot welds. 
     In some embodiments, the flange is connected to a floor contacting portion as an integral unit. In some embodiments the arc of the spring member is also tangent to the floor contacting portion. 
     The arc-shaped portion  112  is deflectable to an arc with less curvature under transverse pressure, which is downward onto an upper surface of the arc-shaped portion. The arc-shaped portion is made of sufficiently resilient material (such as spring metal) so that it returns to its shape with the rest curvature upon removal of the transverse pressure. The doorstop  100  is depicted in  FIG. 1  in its rest configuration with the arc-shaped portion having its rest curvature. The rest curvature need not be constant over the length of the arc-shaped portion and in the illustrated embodiments varies with position along the arc-shaped portion. In an example embodiment, flange  120  and spring member  110  are both made of zinc sheet metal. 
     The flange  120  and arc-shaped portion  112  of the spring member  110  deflect floorward, due to transverse pressure applied to the arc-shaped portion  112  through the flange  120  as a door passes over the doorstop  100 , to allow the door to pass. After the door passes, the arc-shaped portion  112  returns to the rest curvature and the flange  120  returns to the rest configuration. The door-engaging end  124  the flange  120  contacts a vertical face of a door to keep the door in an open position. 
     In this embodiment, the floor contacting end portion  114  of the spring member is coated on its lower surface with a high friction material  116  that inhibits or prevents slippage on a floor where the doorstop  100  is deployed. Any high friction material suitable for preventing slippage on a particular range of floor coverings may be used. For example, in some embodiments, the material  116  is an assembly of tiny hooks that engage fibers in a carpet, such as the hook assembly of hooks and loops materials available commercially from VELCRO™ (Velcro USA Inc., Manchester, N.H.). In some embodiments the high friction material is rubber, such as used in conventional triangular-shaped doorstops to prevent slippage on wood floors. 
       FIG. 2  is a plan view that illustrates the doorstop  100 , according to the same embodiment. The flange is visible from floor contacting end  126  to door engaging end  124 . The attached portion  122  is marked. The left edge of the attached portion  122  represents the leftmost extent of the spring member  110  hidden beneath the flange  120 . Some of the arc-shaped portion  112  of the spring member  110  is visible to the right of the door engaging end  124 . The floor contacting portion  114  of the spring member  110  is also visible at the farthest right. The high friction material is not visible as it lies on the under surface of the floor contacting portion  114 . 
     Although the flange and spring member have a rectangular shape in the plan view of the illustrated embodiment, in other embodiments, other shapes are used, including hourglass shapes that are narrow between the ends  124  and  126  of flange  120 , and trapezoidal shapes with one of the door engaging end  124  and the floor contacting end  126  longer than the other but parallel to each other. In some embodiments the door engaging end  124  is not parallel to the floor contacting end  126 . The length, width and shape of the spring member  110  and flange  120  can be determined by one of ordinary skill in the art by routine experimentation. In a preferred embodiment, the plan views are rectangular, as depicted, with dimensions as follows: width is 9 cm; overall length is 16¾ cm; length of floor contact portion  114  is 3 cm; length of arc-shaped portion  112  is 10 cm; length of flange  120  is 13 cm; distance from attached portion  122  to door-engaging end  124  is 6½ cm. 
       FIG. 3  is an elevation view that illustrates the doorstop  100 , according to the same embodiment. Doorstop  100  includes: spring member  110  with arc-shaped portion  112 , floor contacting portion  114  and high friction material  116 ; and flange  120  with door engaging end  124 , floor contacting end  126  and attached portion  122 . As can be seen in  FIG. 3 , the flange  120  is substantively tangent to the arc-shaped portion  112  at the attached portion  122 . In the illustrated embodiment, the door-engaging end  124  is farther than the attached portion  122  from a plane defined by the floor contacting end portion  114  of the spring member  110   
     Also depicted in  FIG. 3  is floor elevation  399  when the doorstop  100  is deployed for operation, but the floor elevation is not part of the doorstop  100 . 
     Also depicted in  FIG. 3  is the operational range of the doorstop  100  for holding a door in an open position. The doorstop  100  operates to hold a door open for any door that has a bottom height between height  302  above the floor elevation  399  and a height  304  above the floor elevation  399 . For a door with a bottom height less than height  302 , the arc-shaped portion is deflected so far as to loss its resilience to return to its original rest curvature. The height  302  can be determined by one of ordinary skill in the art through routine experimentation. For a door with a bottom height greater than height  304 , the door engaging end  124  of flange  120  will fail to engage the door, and the door will be free to return to its closed position. 
     A person of ordinary skill in the art can chose designs so that height  302  and height  304  cover a sufficient range of heights to provide door stopping functionality for a commercially useful range of door bottom heights. For example, rest curvature for arc-shaped portion  112  at the attached portion  122  and length of flange  120  from attached portion  122  to door engaging end  124  can be selected to provide for a large height  304 . In a preferred embodiment, the height  302  is about one centimeter (e.g., about ½ inch) and the height  304  is about 2½ cm (about 1¼ inch). 
     An advantage of this embodiment over Sasgen is that the same device works for a wider range of door bottom heights. 
       FIG. 4  is a diagram that illustrates the operation of the doorstop  100  as a door passes over, according to the same embodiment. As shown also in  FIG. 3 , in a rest configuration, without transverse pressure, doorstop  100  includes: spring member  110  with arc-shaped portion  112 , floor contacting portion  114  and high friction material  116 ; and flange  120  with door engaging end  124 , floor contacting end  126  and attached portion  122 . 
     When a door moves across the doorstop  100  from left to right, the doorstop deflects to allow the door to pass. This configuration is depicted in  FIG. 4  by door  490   a  in a first position. The door has width  494  and a vertical face  492   a . The door  490   a  applies transverse pressure to flange  120  that transfers the pressure to the arc-shaped portion  112  of spring member  110  through the attached portion  122 . In response, the arc-shaped portion  112  deflects to position indicated by dotted line  412  and the flange deflects to position indicated by the dotted line  420 . The range of movement of the door engaging end from the rest configuration to the deflected configuration is indicated by distance  484 . In a preferred embodiment, the flange is made of material that is slick enough to not significantly oppose the sliding of the door over the flange  120 . 
     The floor contacting portion  114  stays in position because of the high friction material  116  in contact with the floor. The floor contacting end  126  of flange  120  moves along the floor to accommodate the deflection. This range of along floor motion is indicated by the distance  482 . In other embodiments, the high friction material is on the floor contacting end  126  of flange  120  and not on the floor contacting end portion  114  of the spring member  110 , so that the latter end slides when the doorstop is compressed by the door passing over. Thus, it is desirable that only one of the floor contacting end  126  and the floor contacting portion  114  of the spring member is coated with high friction material  116 . 
     Because the door slides easily over the illustrated embodiment and automatically compresses the doorstop as the door is opened, a user does not have to depress the doorstop by hand or foot, as is often necessary for the doorstop of Hum. 
     When the door passes past the door engaging end, as indicated by the dark horizontal arrow, this configuration is depicted in  FIG. 4  by door  490   b  in a second position. The door no longer applies a transverse pressure to flange  120  and the spring member and flange return to their rest configuration. The door engaging end  124  prevents the door  490   b  in the second position from returning to the left and closing. Thus the store stays in the open position. 
     These embodiments enjoy advantages over prior art doorstops. For example, an advantage of several embodiments over Sasgen is that a single embodiment works over a larger range of door bottom heights. An advantage of several embodiments over Hum is that a user need not compress the doorstop with the user&#39;s foot as the door is positioned over the doorstop, as stated by Hum. The door automatically compresses the doorstop as the door is opened. 
       FIG. 5  is an elevation view that illustrates a doorstop  500 , according to a different embodiment. Doorstop  500  includes a spring member  510  and a flange  510 . Spring member  510  includes a floor contacting end portion  114  and high-friction material  116  as in spring member  110 . However, the spring member  310  includes an arc-shaped portion  512  that extends to a second floor contacting portion  516  aligned with the floor contacting end  126  of flange  520 . The flange  520  includes the door engaging end  124  and the floor engaging end  126  as in flange  120 . However the flange  520  includes a more extensive attached portion  522 , and door protection material  524 . The door protecting material  524  is any material that serves to reduce scratching on a vertical door face (e.g., face  492   b ) when in contact with the vertical door face. In some embodiments, the door protecting material is a downward curve in the end  124  to prevent presenting a sharp edge. In some embodiments, the door protecting material is a softer material than the material that makes up the rest of flange  520 . The inventor has determined that with a zinc sheet metal flange, no different door protecting material  524  is needed to prevent scratches. 
       FIG. 6  is an elevation view that illustrates a doorstop  600 , according to another different embodiment. The doorstop  600  includes spring member  510 , as described above, and flange  620 . Flange  620  includes the door engaging end  124  and the attached portion  122  of flange  120 . However, flange  620  omits the floor contacting end  116  of flange  120 ; and ends at end  626  at an edge of the attached portion  122 . In the illustrated embodiment, the end  626  is sloped to reduce the chances of or entirely avoid catching a door passing over. 
       FIG. 7  is an elevation view that illustrates a doorstop  700 , according to still another different embodiment. The doorstop  700  includes spring member  710  and flange  720 . The spring member  710  includes floor contacting portion  114  and arc-shaped portion  512 , described above, but excludes high friction material  116  on the lower surface of floor contacting portion  114 . Flange  720  includes the door engaging end  124  and floor contacting end  124  of flange  120 , and the extended attached portion  522  of flange  520 , described above. However doorstop  700  includes a high friction material  716  attached to at least one of the floor contacting end  126  of flange  720  or the floor contacting end  516  of spring member  710 . In this embodiment, the floor contacting portion  114  slides along the floor when the flange  720  is pressed by a passing door bottom, while the floor contacting ends ( 126 ,  516 ) connected to the high friction material  716  remain in place. 
     In the foregoing specification, the invention has been described with reference to specific embodiments thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of the invention. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.