Patent Publication Number: US-6983512-B2

Title: Movable door mounting assembly with trolley locking structure

Description:
TECHNICAL FIELD 
     The present invention relates to movable door installations and more particularly to mounting assemblies for movable door installations. 
     BACKGROUND OF THE INVENTION 
     Movable door mounting structure are used in both sliding door installations and folding door installations. Both installations allow the door to move along a horizontal track mounted at the top of a door opening, with the door being suspended from the track via the mounting assembly. Sliding door installations usually include two separate mounting structures, one at each end of the door, while folding door installations have a hinge connecting an outer door panel with a pivoting door panel and a movable mounting structure attached to the pivoting door panel. 
     The mounting structure usually includes two cooperating assemblies: a trolley assembly inserted into the horizontal track and studs mounted to the top of the door. When the door is inserted into the door opening, the studs engage with the trolley assembly to suspend the door from the track. 
     Because the trolley assembly has wheels that roll on the track, a user may have to chase the loose trolley with the stud while positioning the door in the door opening. This problem is aggravated by the bulk of the door, which makes it difficult to align the stud with the moving trolley assembly. Some users solve this problem by securing the trolley to the track with tape before inserting the stud, but removing the tape is difficult once the door is hung in the door opening. As a result, any tape residue on the track or the trolley prevents the trolley from moving smoothly. 
     There is a desire for a movable door mounting structure that makes it easier to attach a movable door panel into a door opening. 
     SUMMARY OF THE INVENTION 
     Accordingly, one embodiment of the invention is directed to a movable door mounting assembly that has a mounting structure movably supported on a track disposed in a door opening. A movable door panel is suspended from the track by the mounting structure, which includes a stud assembly and a trolley assembly. The trolley assembly includes a spring-biased cam piece that pivots between a normal position, which allows the trolley assembly to move freely on the track, and a locked position, which causes a locking surface on the cam piece to frictionally engage with a top surface of the track and hold the trolley assembly in place. 
     The stud assembly includes a catch designed to engage with the cam piece when the mounting assembly is fully assembled. During door mounting, a user pivots the cam piece into the locking position, preventing the trolley assembly from moving while the user inserts the stud assembly. When the door panel is pushed upward to engage the stud assembly with the trolley assembly, the upward movement releases the cam piece from its locked position and, at the same time, positions the catch so that it engages with the cam piece when the door panel is released and allowed to move back downward. 
     As a result, the invention provides a simple locking structure that makes it easier to connect the trolley assembly with the stud assembly to hang a movable door panel. Further, the automatic releasing feature of the locking structure eliminates the need to remove any components retaining the trolley assembly once the door panel has been hung. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of one embodiment of a door mounting assembly according to one embodiment of the invention; 
         FIG. 2  is a section view taken along line  2 – 2 ′ of the door mounting assembly shown in  FIG. 1 . 
         FIG. 3  is a perspective view of a portion of a mounting structure in the door mounting assembly according to one embodiment of the invention; 
         FIG. 4  is an exploded view of the structure shown in  FIG. 3 ; 
         FIGS. 5   a  and  5   b  are section views taken along line  5 – 5 ′ of the mounting structure shown in  FIG. 3  at different stages of assembly. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       FIG. 1  is an example of a twin sliding door installation having a door mounting assembly  100  according to one embodiment of the invention. Note that the door mounting assembly  100  can also be applied to folding doors. In one embodiment, the door mounting assembly  100  includes a track  102  and a mounting structure  104 . The mounting structure  104  includes a trolley assembly  106  and a stud assembly  108 , allowing a door  110  to be mounted within a door opening. The track  102  is mounted in a doorway opening along a desired travel path for the mounting structure  104 . The mounting structure  104  is movable within the track  102 , allowing the door  110  to slide and/or pivot. In the embodiment shown in  FIG. 1 , two mounting structures  104  are inserted into the track  102  through a gap  112  at the end of the track  102 . 
       FIG. 2  is a section view of the track  102  and the trolley assembly  106  taken along line  2 – 2 ′ in  FIG. 1 . In the illustrated embodiment, four wheels  200  are mounted to two parallel axles  202  that are held by a center plate  204 . The wheels  200 , axles  202  and center plate  204  together form a carriage  205 . A cam piece  206  is mounted to at least one of the axles  202  to form the trolley assembly  106 . The cam piece  206  is rotatable about the axle  202 . Note that the carriage  205  is not limited to the structure shown in  FIG. 2 , but can incorporate any configuration that allows the trolley assembly  106  to move smoothly along the track  102 . 
     The door mounting assembly  100  may incorporate any track  102  structure known in the art. Alternatively, the track  102  may incorporate several features that improve performance of the mounting assembly  100 . As shown in  FIG. 2 , the track  102  may include longitudinal guides  208  that extend along the length of side inner surfaces of the track  102  to guide the trolley wheels  200  and prevent the ends of the axles  202  from scraping against the sides of the track  102 . The guides  208  can also increase the rigidity of the track  102 . Optional grooves  212  may be formed in the guides  208  so that a track cover  214  can be attached to the side outer surface of the track  102 , if desired. Longitudinal ribs  216  may also be formed on an inner surface, such as a top inner surface  218 , of the track  102  to provide added friction for the cam piece  206  to hold the trolley assembly  206  in place, as will be described in greater detail below. Other frictional surfaces may be formed or attached to the track instead of the ribs  216  on the inner surface  218  without departing from the scope of the invention. Further, although the embodiment shown in the Figures show the frictional surface on the top inner surface  218  of the track  102 , the frictional texture may be disposed on or attached to the side inner surfaces of the track  102  instead of or in addition to the top inner surface  218 . Also, the frictional texture may, if desired, be formed in a separate component that is attached to the track  102 ; this allows the frictional texture to be formed in a material that is different from the track material. 
     Referring to  FIGS. 3 and 4 , the stud assembly  108  is designed to be attached to the door  110  and to couple with the trolley assembly  106 . The stud assembly  108  includes a stud head  300  held in a pocket  302  of a door plate  304 , which is designed to be attached to the door  110 . The door plate  304  may include one or more slots  305  to accommodate screws or other similar attachment structures (not shown) attaching the door plate  304  to the top of the door  110 . The stud head  300  supports an adjustable stud  306  via a threaded or other engagement structure, and a movable catch  308  is movably attached to the adjustable stud  306 . The catch  308  can move up and down the adjustable stud  306  freely. In one embodiment, the catch  308  extends through a hole  310  in the center plate  204  of the trolley assembly  106  and has a stud catch surface  312  designed to engage with the cam piece  206 . 
     As noted above, the cam piece  206  is rotatable about the axle  202  holding it to the trolley assembly  106 . The cam piece  206  also has three cam surfaces: a bearing surface  313 , a cam catch surface  314 , and a locking surface  315 . The cam piece  206  is also biased by a spring  316  placed in a hole  317  in the cam piece  206 . A lever portion  318  on the cam piece  206  allows a user to pivot the cam piece  206  with the fingers. If there are no forces applied to the cam piece  206 , the spring  316  biases the cam piece  206  so that the bearing surface  313  contacts the center plate  204 . 
       FIGS. 5   a  and  5   b  illustrate the operation of the inventive door mounting assembly  100  at different stages of engagement. For clarity, the Figures show an assembly  100  having one cam piece  206 ; however, a preferred embodiment of the invention has two cam pieces  206 , one attached to each axle  2002 . Initially, the trolley assembly  106  is placed in the track  102  and the lever  318  on the cam piece  206  is squeezed downward against the biasing force of the spring  316  until the locking surface  315  engages with the top inner surface  218  of the track  102 . The friction between the locking surface  315  and the track surface  218  immobilizes the trolley assembly  106  on the track  102 . If the track surface  218  has longitudinal ribs  216 , the ribs  216  help create a better grip between the locking surface  315  on the cam piece and the track surface  218 . 
     Next, as shown in  FIG. 5   a , the user engages the stud assembly  108  with the trolley assembly  106  by raising the door  110 , with the stud assembly  108  attached, so that the catch  308  extends through the hole  310  in the trolley assembly  106 . As the door  110 , and therefore the stud assembly  108 , move upward as shown by arrow A, the stud catch surface  312  moves above the cam catch surface  314 . The position and shape of the cam piece  206  allows the catch  308  to move freely past the cam piece  206  while the cam piece  206  is in the locked position. At the same time, the door plate  304  pushes against the lever  318 , overcoming the friction force between the locking surface  315  and the track surface  218 . The biasing force of the spring  310  allows the cam piece  206  to rotate back to its normal position, when the door  110  is released and allowed to drop down via gravity. 
     As shown in  FIG. 5   b , however, the stud catch surface  312  prevents the catch  308  from slipping back out of the hole  310  in the trolley assembly  206  when the door drops. Instead, the stud catch surface  312  engages with the cam catch surface  314  as the stud assembly  108  moves downward, as indicated by arrow B. When the cam piece  206  returns to its normal position, with the bearing surface  313  contacting the center plate  204 , the engagement between the stud catch surface  312  and the cam catch surface  314  supports the door  310  as it hangs from the trolley assembly  206 . The rotation of the cam piece  206  also disengages locking surface  315  and the track surface  218 , automatically releasing the trolley assembly  106  and allowing it to move freely in the track  102 . The adjustable stud  306  may be rotated within the catch  308  by the user to fine-tune the door&#39;s position. 
     To remove the door  110 , the steps in  FIGS. 5   a  and  5   b  are simply reversed. Lifting the door  110  while squeezing the lever  318  releases the catch  308  and disengages the cam catch surface  314  away from the stud catch surface  312 . Squeezing the lever  318  also locks the trolley assembly  106  on the track  102 , holding it in place while the door  110  is being removed. Maintaining the separation between the two surfaces  312 ,  314  allows the stud assembly  310  to drop out of the trolley assembly  206 , releasing the door  110 . At the same time, the locking surface  315  engages with the track surface  318 , locking the trolley assembly  216  on the track  102 . 
     As a result, the inventive structure makes it easier to align different portions of the door mounting assembly without requiring the user to chase the trolley assembly along the track or tape the trolley assembly to the track. Instead, the invention integrates a trolley locking structure that is easily accessible, simple to manufacture, and that automatically disengages when the door is hung in place. Further, because the inventive door mounting assembly relies on components (e.g., the cam piece  206  an catch  308 ) having larger bearing surfaces than currently known structures, the invention does not need to rely on expensive high-strength materials to create a reliable mounting assembly. 
     It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. It is intended that the following claims define the scope of the invention and that the method and apparatus within the scope of these claims and their equivalents be covered thereby.