Patent Publication Number: US-9834972-B2

Title: Anti-jumping upper wheel device with double dampers

Description:
FIELD OF THE INVENTION 
     The present invention relates to the field of manufacture of hardware accessory for architectural decoration, especially relates to an upper wheel for a sliding door, and more especially relates to an anti-jumping upper wheel device with double dampers. 
     BACKGROUND OF THE INVENTION 
     There are several kinds of damper assemblies used in cupboard doors (sliding doors), dampers in a general damper assembly for a sliding door are used in relative left and right sides, and therefore the assembly requirement thereof is rigid; and while usually the damper assembly has only one damper and thus has limited damping force. Under the aforementioned prior art, if there is need to enhance damping force, two dampers for a damper assembly in both left and right sides may be required. Accordingly, pulling sheets would be needed to being arranged respectively with the tracks of dampers. As such, the whole structure would get complicated, bringing about higher assembly requirements. 
     In order to overcome the abovementioned defects, applicant of the present invention researched an upper wheel assembly with double dampers for the cupboard door and have a patent (patent No. 201320065103.7) on it, wherein two dampers in parallel are assembled in a cover of the upper wheel assembly with double dampers for cupboard door, and a pulling unit is assembled to a common fore-head of the two dampers which can pull or push both dampers simultaneously, so as to achieve the “stretch” and damping effect with cooperation of other units. For assembling, fixing the upper wheel assembly with double dampers on upper end of the door leaf, and fixing a pulling unit upside-down in the upper track by screw, and plugging a sliding pillar of the pulling unit into a circular arc groove of a damper sliding sheet of the upper wheel assembly with double dampers, in order to pull and push the damper sliding sheet. 
     However, with applying of the above-mentioned patented technology, the applicant found a problem to be solved that the door leaf jumps at the time of being open and closed because of accelerated velocity. In addition, problem of assembly of the pulling unit also needs to be solved, because assembly of the pulling unit into the upper track is not firm enough that the pulling unit is prone to drop when the door is pulled and pushed for much times. Moreover, the pulling pillar should be long enough to plug into the circular arc groove of the damper sliding sheet, while in fact it is not long enough as it is fixed on a base of the pulling unit which is assembled in the upper track, and it thus is prone to fall off the circular arc groove, and therefore the problem about the effective length of the pulling pillar of the pulling unit needs to be solved. 
     For the above, it is necessary to improve the above-mentioned technology. 
     SUMMARY OF THE INVENTION 
     In order to solve the problem of door leaf jumping in the prior art, the patent filed on 15th Apr., 2013 by the applicant named “anti-jumping upper wheel assembly with double dampers for cupboard door” (Application No. CN201320188516.4) provides a technical solution: mounting an anti-jumping roller vertically in the cover of the upper wheel assembly with double dampers for cupboard door, and the patent also provides a double-plate pulling unit to solve the problem about assembly of the pulling unit and effective length of the pulling pillar, but with applying defects also exit. For this purpose, the applicant further researched and got an improved double-plate pulling unit on which a patent application on 8 th  Jul., 2013 (Application No. CN201320403640.8) is filed, which can adjust height of the pulling pillar and thus ensure effective length of the pulling pillar, and make assembly easier and firmer. 
     The present invention claims right of priority of the above-mentioned two patents, whose technical solution will be cited into the present application. 
     The present invention aims to provide an anti-jumping upper wheel assembly with double dampers, which can anti jumping of the door leaf, and whose pulling unit is easy to be assembled and is firm, and whose pulling unit cooperates well with the damper sliding unit. 
     In order to achieve the above aim, the present invention provides the following technical solution: 
     An anti-jumping upper wheel device with double dampers comprising an anti-jumping upper wheel assembly with double dampers and a pulling unit; wherein the anti-jumping upper wheel assembly comprises an upper wheel plate, a upper wheel and an upper wheel cover, wherein the upper wheel and the upper wheel cover are mounted on said upper wheel plate; dampers are connected to a damper sliding unit at an end and mounted in longitudinal direction in said upper wheel cover on said upper wheel plate; 
     the pulling unit are adapted for an upper track in which a door leaf is mounted, such that the pulling unit is capable of pulling said damper sliding unit; wherein,
         an extension spring is mounted in parallel with and between said two dampers; a connecting unit is connected to said damper sliding unit, and heads of drawbars of said dampers and the corresponding end of said extension spring are connected to said connecting unit;       

     an anti-jumping roller is mounted onto said upper wheel cover, the anti-jumping roller having a horizontal axle being vertical with the direction that the door leaf moves and an upper part of which protruding out of top face of said upper wheel cover; 
     said pulling unit is a pulling unit with double plates, which is comprised of a baseplate of pulling unit and a pillar plate of pulling unit mounted on the baseplate; a pulling pillar which is configured to pull said damper sliding unit is fixed vertically on said pillar plate of pulling unit; 
     both ends in longitudinal direction of said baseplate of pulling unit are cut into a plurality of longitudinal and parallel branch plates; each of the parallel branch plate has a connecting hole, and a connecting elastic unit is connected in parallel to the plurality of longitudinal and parallel branch plates; 
     said connecting elastic unit is comprised of a baseplate of elastic unit, a left erect plate and a right erect plate, wherein the left erect plate and the right erect plate are respectively fixed on both ends of said baseplate of elastic unit; said baseplate of elastic unit further comprises a plurality of sub-plates which are same in quantity as said branch plates at corresponding ends of said baseplate of pulling unit; and at least one sub-plate is raised or dent with relative to other sub-plates so that all said sub-plates are not in the same plane in order to achieve overlapping connection by some sub-plates fitting in top face of corresponding branch plates and other sub-plate fitting in bottom face of corresponding branch plates; 
     the plurality of sub-plates respectively fitting to the plurality of longitudinal and parallel branch plates so that said connecting elastic unit is connected to said baseplate of pulling unit; said sub-plates have assembly holes or raised heads fitting to said connecting holes of said branch plates; 
     lug bosses are respectively mounted on outer surfaces of said left erect plate and said right erect plate, and a vertical distance between the outer surface of said lug bosses of said left erect plate and the outer surface of said right erect plate is identical with a width of said upper track in vertical direction. 
     Preferably, both ends in longitudinal direction of said baseplate of pulling unit are cut into three longitudinal and parallel branch plates, and said baseplate of elastic unit of said connecting elastic unit is comprised of three sub-plates, the three sub plates being a left baseplate fixed to said left erect plate, a right baseplate fixed to said right erect plate, and a middle baseplate fixed between said left baseplate and said right baseplate. 
     Preferably, said left baseplate is located in the same plane with said right baseplate; said middle baseplate is raised with respect to said left baseplate and said right baseplate, such that said branch plate in the middle may fits to an bottom of said middle baseplate and said branch plates at both sides may respectively fit to top surfaces of said left baseplate and said right baseplate. 
     Preferably, said left baseplate and said right baseplate each has a raised head, said raised heads respectively being fitted to and connected to said connecting holes in two of said three longitudinal and parallel branch plates at sides; an assembly hole is provided on said middle baseplate to fit to said connecting hole in one of said three longitudinal and parallel branch plates in the middle, and a screw goes through said assembly hole and said connecting hole to achieve assembling. 
     Preferably, a guiding unit and an internal is provided upright on the baseplate of pulling unit, and a hex stud in parallel with the guiding unit are fixed on said baseplate of pulling unit; a guiding hole fitting to said guiding unit and a screw hole fitting to said internal hex stud are correspondingly mounted to said pillar plate of pulling unit, said guiding unit and said internal hex stud go through said guiding hole and said screw hole respectively, and a distance between said pillar plate of pulling unit and said baseplate of pulling unit may be adjustable by rotating said internal hex stud. 
     Preferably, said lug boss may be shaped as a cuboid. 
     Preferably, a “+” symbol-shaped groove hole is provided onto said upper wheel cover at an end onto which a groove for sliding is mounted, and said anti-jumping roller is arranged in said “+” symbol shaped groove hole. 
     Preferably, two dampers are arranged in parallel in longitudinal direction within said upper wheel cover on said upper wheel plate, and the heads of drawbars of said two dampers are connected to said damper sliding unit; said damper sliding unit has a plugging hole fitting to said pulling unit; a groove for sliding corresponding to said damper sliding unit is provided on aid upper wheel cover; said plugging hole is positioned in said groove for sliding, and said pulling unit is capable of passing through said groove for sliding and plug into said plugging hole. 
     Preferably, said damper sliding unit has a fitting pillar; a guiding groove used for guiding said fitting pillar is provided on inner surface of said upper wheel cover, said guiding groove having a bent portion at an end, and said bent portion and said damper sliding unit being structured such that said fitting pillar is fitted to said bent portion as sliding into said bent portion and can get out as sliding to opposite direction. 
     The present invention has the following advantages: special structured pulling unit with double plates is easy to be assembled in the upper track and very firm, in order that the pulling unit can function well and pull the damper sliding unit to move, and wherein the anti-jumping roller can prevent the door leaf from jumping at the time of being open and closed, to ensure the door leaf move smoothly, and the anti-jumping upper wheel device with double dampers is simple and compact in structure and is with low cost. Other advantages of the present invention will be described in the following preferred examples. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front view of the anti-jumping upper wheel assembly with double dampers of the anti-jumping upper wheel device with double dampers. 
         FIG. 2  is a top view of the anti-jumping upper wheel assembly with double dampers in  FIG. 1 . 
         FIG. 3  is a left view of the anti-jumping upper wheel assembly with double dampers in  FIG. 1 . 
         FIG. 4  is a right view of the anti-jumping upper wheel assembly with double dampers in  FIG. 1 . 
         FIG. 5  is a graphic model of the anti-jumping upper wheel assembly with double dampers in  FIG. 1 . 
         FIG. 6  is a graphic model of the anti-jumping upper wheel assembly with double dampers in  FIG. 1  without the upper wheel plate, wherein its extension spring and dampers are in non tension state, and wherein an exploded view of position of the upper wheel is shown. 
         FIG. 7  is a diagrammatic sketch of the upper wheel cover of the anti-jumping upper wheel assembly with double dampers in  FIG. 1 . 
         FIG. 8  is a front view of the pulling unit of the anti-jumping upper wheel device with double dampers, wherein the pulling unit is shown upside down. 
         FIG. 9  is a top view of the pulling unit in  FIG. 8 . 
         FIG. 10  is an upward view of the pulling unit in  FIG. 8 . 
         FIG. 11  is a right view of the pulling unit in  FIG. 8 . 
         FIG. 12  is a left view of the pulling unit in  FIG. 8 . 
         FIG. 13  is a graphic model of the pulling unit in  FIG. 8 . 
         FIG. 14  is a front view of the connecting elastic unit of the pulling unit in  FIG. 8 . 
         FIG. 15  is a top view of the connecting elastic unit in  FIG. 14 . 
         FIG. 16  is an upward view of the connecting elastic unit in  FIG. 14 . 
         FIGS. 17 and 18  are respectively a left view and a right view of the connecting elastic unit in  FIG. 14 . 
         FIG. 19  is a graphic model of the connecting elastic unit in  FIG. 14 . 
         FIG. 20  is a whole view of the anti-jumping upper wheel device with double dampers of the present invention, wherein the anti-jumping upper wheel assembly with double dampers is apart with the pulling unit. 
         FIG. 21  is a whole view of the anti-jumping upper wheel device with double dampers of the present invention, wherein the pulling pillar of the pulling unit are plugged into the plugging hole of the damper sliding unit of the anti-jumping upper wheel assembly with double dampers. 
         FIG. 22  is a diagrammatic view of the anti-jumping upper wheel device with double dampers of the present invention assembled respectively on the door leaf and the upper track. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Components and parts represented by reference signs in the drawings are as follows. 
     Anti-jumping upper wheel assembly with double dampers  10 , pulling unit  20 ; 
     upper wheel plate  11 , upper wheel  12 , upper wheel cover  13 , damper  14 , damper sliding unit  15 , extension spring  16 , groove for sliding  131 , “+” symbol-shaped groove hole  1310 , assembling groove  132 , bent portion  1320 , assembling grooves for dampers  133 , 134 , assembling grooves for extension spring  135 , plugging hole  150 , connecting unit  151 , connecting holes for drawbars of dampers  1510 ,  1511 , connecting hole for extension spring  1512 , anti-jumping roller  17 ; 
     baseplate of pulling unit  21 , pillar plate of pulling unit  22 , pulling pillar  221 , guiding unit  211 , internal hex stud  212 , guiding hole  222 , screw hole  223 , extension part  2220 , screw  224 , screw  225 , end in longitudinal direction  213 , three longitudinal branch and parallel plates  2131 ,  2132 ,  2133 , end in longitudinal direction  214 , three longitudinal branch and parallel plates  2141 ,  2142 ,  2143 , connecting holes a, b, c; 
     connecting elastic unit  24 , connecting elastic unit  23 , baseplate of elastic unit  231 , left erect plate  232 , right erect plate  233 , left baseplate  2311 , right baseplate  2312 , middle baseplate  2313 , raised heads  23110 ,  23120 , assembly hole  23130 , lug bosses  2320 ,  2330 , door leaf of cupboard door A, upper track B. 
     Preferred embodiments of the present invention will be described in the following with the drawings. 
       FIG. 20  and  FIG. 21  show whole views of the anti-jumping upper wheel device with double dampers of an embodiment of the present invention, which is comprised of two parts: an anti-jumping upper wheel assembly with double dampers  10  assembled at top end of the door leaf of a sliding door in use, and a pulling unit  20  assembled in the upper track in use.  FIGS. 1 to 7  show the ant-jump upper wheel assembly with double dampers  10  and its components,  FIGS. 8 to 13  show the pulling unit  20 , and  FIGS. 14 to 19  show the connecting elastic unit  23  of the pulling unit  20 .  FIG. 22  shows a diagrammatic view of the anti-jumping upper wheel device with double dampers being assembled to the door leaf A and the upper track B. 
     Next, the anti-jumping upper wheel assembly with double dampers  10  and the pulling unit  20  will be described respectively. 
     (I) The Anti-Jumping Upper Wheel Assembly with Double Dampers  10   
     As shown in  FIGS. 1 to 8 , the anti-jumping upper wheel assembly with double dampers  10  is comprised of an upper wheel plate  11 , an upper wheel  12  and an upper wheel cover  13  mounted on the upper wheel plate  11 , and a damper  14  an end of which is connected to a damper sliding unit  15  is mounted in longitudinal direction in the upper wheel cover  13  on the upper wheel plate  11 . When the anti-jumping upper wheel assembly with double dampers  10  is assembled on the top end of the door leaf, the upper wheel  12  can fit to and slide along the upper track in which a door leaf is assembled. 
     Preferably, in the present invention, two dampers  14  are mounted in longitudinal direction in parallel in the upper wheel cover  13  on the upper wheel plate  11 , the damper sliding unit  15  is connected to ends of drawbars of the two dampers, and damping effect is enhanced because of these two dampers. In addition, an extension spring  16  which can also be pulled and pushed by the damper sliding unit  15  is mounted in parallel with and between two dampers  14 . Damper assembling grooves  133 ,  134  for two dampers  14  and an extension spring assembling groove  135  for the extension spring  16  are mounted in the upper wheel cover  13 . The damper sliding unit  15  is connected with a connecting unit  151  which has connecting holes for dampers&#39; drawbars  1510 , 1511  and a connecting hole for extension spring  1512 , ends of the drawbars of two dampers  14  and the corresponding end of the extension spring  16  are respectively connected to the connecting holes for dampers&#39; drawbars  1510 , 1511  and the connecting hole for extension spring  1512 , in order that the dampers  14  and the extension spring  16  can be pulled and pushed by the damper sliding unit  15 . 
     A groove for sliding  131  is mounted in the upper cover  13  at the position corresponding to the damper sliding unit  15 , the groove for sliding  131  is mounted at longitudinal middle position of the upper wheel cover  13  i.e. middle position between two dampers  14 , and aligns with position of the extension spring  16 . 
     Wherein, damper sliding unit  15  has a plugging hole  150  and a fitting pillar. Wherein, the plugging hole  150  is positioned in the groove for sliding  131 , so that the pulling pillar (will be described in the following) of the pulling unit  20  can go through the groove for sliding  131  and plug into the plugging hole  150  to pull the damper sliding unit  15 . A guiding groove  132  for guiding the fitting pillar is mounted to inner surface of the upper wheel cover  13 , the guiding groove  132  has a bent portion  1320  at the last end which fits to the above-mentioned fitting pillar of the damper sliding unit  15 , and the bent portion  1320  and the damper sliding unit  15  are proper structured in order that the fitting pillar can be fitted and locked in the bent portion  1320  when it slides into the bent portion  1320  and at which moment the extension spring  16  reaches to its maximum and the damper  14  is “strung”, and the fitting pillar can get out of the bent portion  1320  when it is being pushed on reverse direction and at this moment the damper is “unhooked” and acts damping effect. The damper sliding unit should have proper structure to satisfy the above mentioned requirements of function and assembly, Chinese patent No. ZL201320065103.7 provides a preferred example of the damper sliding unit whose technical solution can be cited in the present invention and will not be described in detail, and the present invention of course can use other equivalent structures. 
     At the minute that the door leaf is being closed and open, the door leaf will jump tempestuously because of a very strong accelerated speed brought then and a gap between the assembled door leaf and the upper track. The applicant thus provides an easy and reliable solution as follows after tests for times. 
     An anti-jumping roller  17  is mounted in the upper wheel cover  13 , a fixed axle of which is vertical with direction that the door leaf moves (longitudinal direction of the anti-jumping upper wheel assembly with double dampers  10 ), and the anti-jumping roller rotates around the fixed axle; moreover, an upper part of the anti-jumping roller  17  protrudes out of top face of the upper wheel cover. The anti-jumping roller  17  is a general rotatable wheel, and preferably a plastic wheel, the height thereof protruding out of the top face of the upper wheel cover  13  is equal to distance between the top face of upper wheel cover  13  and surface of a pillar plate of pulling unit of the pulling unit  20  which will be described in the following, the anti-jumping roller  17  rotates on the pillar plate of pulling unit along the direction that the door leaf moves and accordingly the door leaf has no space to jump, therefore the door leaf jumping at the time of being opened and closed is avoid, and a very great effect is obtained with applying. As a preferred embodiment, a “+” symbol shaped groove hole  1310  is mounted to the upper wheel cover in the end to which the groove for sliding  131  is mounted, and the anti-jumping roller  17  is assembled in the “+” symbol shaped groove hole  1310 . 
     (II) The Pulling Unit  20   
     As shown in  FIGS. 9 to 14 , the pulling unit  20  is a pulling unit with double plates, which is comprised of a baseplate of pulling unit  21  and a pillar plate of pulling unit  22  assembled below the baseplate of pulling unit  21 ; a pulling pillar  221  fitting to the plugging hole  150  of the damper sliding unit  15  is fixed vertically on the face of pillar plate of pulling unit  22 . 
     Wherein, the pulling pillar  221  is a very important functional part, and it can be inserted into the plugging hole  150  to pull the damper sliding unit  15  and make the damper  14  “strung”, can get out of the plugging hole  150  when moving on after the damper is “strung”, and can force the damper sliding unit on reverse direction of sliding to make the damper act damping function. Actual length of the pulling pillar  221  is usually not the effective length plugged into the plugging hole  150  because of limit by assemble, but the structure of double plates can make the pillar plate of pulling unit  22  be closer to the top of the door leaf in order to increase the effective length of the pulling pillar while the baseplate of pulling unit  21  is assembled to the top surface of the upper track. 
     Preferably, vertically upright guiding units  211  and an internal hex stud  212  in parallel therewith are fixed on the baseplate of pulling unit  21 , guiding holes  222  fitting to the guiding units  221  and a screw hole  223  fitting to the internal hex stud  212  are correspondingly mounted to the pillar plate of pulling unit  22 , and the guiding units  211  and the internal hex stud  212  go through the guiding holes  222  and the screw hole  223  respectively to protrude out of the pillar plate of pulling unit  22 ; more preferably, an extension part  2220  for each guiding unit  211  is mounted around the respective guiding hole  222  on the pillar plate of pulling unit  22 . In the present embodiment, preferably, two guiding units  211  are mounted, and more preferably, the guiding units are cuboid; and one end of the internal hex stud  212  is restricted in the baseplate of pulling unit  21  and can only rotate. 
     In addition, the pillar plate of pulling unit  22  is comprised of a plastic board and a metal baseplate overlapped both of which are fixed together by a screw marked by  224  in figures from bottom to top and a screw marked by  225  from top to bottom. 
     Turn around the above-mentioned internal hex stud  212 , driving it to mesh transmission with the screw hole  223 , the pillar plate of pulling unit  22  thus moves upward or downward with relative to the baseplate of pulling unit  21 , and the effective length of the pulling pillar  221  fixed on the pillar plate of pulling unit  22  will be elongated or shorten in order that it can fit to the damper sliding unit  15  and plug into the plugging hole  150  and therefore can pull the damper sliding unit  15  effectively to work; and whole height of the pulling unit  20  can also be adjusted to fit different assembly width. 
     Preferably, in order to fix the pulling unit  20  on the upper track, the end  213  in longitudinal direction of the baseplate of pulling unit  21  is cut into three longitudinal branch and parallel plates  2131 ,  2132 ,  2133 , the end  214  in longitudinal direction of the baseplate of pulling unit  21  is cut into three longitudinal branch and parallel plates  2141 ,  2142 ,  2143 , and a connecting hole is mounted to each branch plate of each end in longitudinal direction; a connecting elastic unit  23  and a connecting elastic unit  24  are respectively connected to the three longitudinal branch and parallel plates of both ends of the baseplate of pulling unit  21 . Since structure of the end  213  in longitudinal direction and the connecting elastic unit thereon are mainly identical with that of the end  214  in longitudinal direction and the connecting elastic unit thereon, thus only take the end  213  in longitudinal direction for example to illustrate the structures next. 
     As shown in  FIGS. 9 to 14 , three longitudinal branch and parallel plates  2131 ,  2132 ,  2133  of the end  213  in longitudinal direction of the baseplate of pulling unit  21  respectively has a connecting hole a, b, c, the connecting elastic unit  23  is connected to the three longitudinal branch and parallel plates, and the connecting elastic unit  23  is made of elastic material which is good for assembly in the upper track steadily. 
     As shown in  FIGS. 15 to 20 , the connecting elastic unit  23  is comprised of a baseplate of elastic unit  231 , and a left erect plate  232  and a right erect plate  233  which are respectively fixed on both ends of the baseplate of elastic unit  231 , the baseplate of elastic unit  231  has a left baseplate  2311  fixed with the left erect plate  232 , a right baseplate  2312  fixed with the right erect plate  233 , and a middle baseplate  2313  mounted between the left baseplate  2311  and the right baseplate  2312 . The connecting elastic unit  23  is made in a whole. 
     Wherein, the left baseplate  2311 , the middle baseplate  2313  and the right baseplate  2312  respectively fit to the branch plates  2131 ,  2132 ,  2133  in parallel in longitudinal direction, in order that the connecting elastic unit  23  can be overlapped and connected to the baseplate of pulling unit  21 ; each of the left baseplate  2311 , the middle baseplate  2313  and the right baseplate  2312  has an assembly hole or a raised head fitting to the connecting holes a, b, c of the corresponding branch plate. 
     In the present example, the left baseplate  2311  and the right baseplate  2312  are in the same plane, the middle baseplate  2313  raises from the left baseplate  2311  and the right baseplate  2312 , so that the middle branch plate  2132  can fit to bottom of the middle baseplate  2313  and the branch plates  2131 ,  2133  in both sides can fit to top of the left baseplate  2311  and the right baseplate  2312  as connecting in parallel. The left baseplate  2311  and the right baseplate  2312  respectively have raised heads  23110 ,  23120  which respectively fit to and connect to the connecting holes a, c of two branch plates  2131 ,  2133  in both sides of the three longitudinal branch and parallel plates; the middle baseplate  2313  has an assembly hole  23130  fitting to the connecting hole b of the branch plate  2132  in the middle of the three longitudinal branch and parallel plates, and a screw passes through the assembly hole  23130  and the connecting hole b to assemble. 
     Of course, in the present example of the present invention, the middle baseplate can dent with relative to the left and the right baseplates, so that the branch plate in the middle can fit to top of the middle baseplate and the branch plates in two sides can respectively fit to bottom of the left and the right baseplate when connecting in parallel. In other examples of the present invention, it also can be that one of the left, the middle and the right baseplates has an assembly hole to connect with corresponding branch plate by screw and the other two of them has raised heads to connect in the connecting hole of corresponding branch plates; and the like. 
     In other examples of the present invention, both ends in longitudinal direction of the baseplate of pulling unit can be cut into more than three longitudinal branch and parallel plates in some situations, each of which has a connecting hole; and a connecting elastic unit is overlapped and connected in parallel to the more than three longitudinal branch and parallel plates of each end in longitudinal direction of the baseplate of pulling unit. Accordingly, elastic baseplate of the connecting elastic unit has more than three corresponding sub-plates which is same in quantity with the branch plates of corresponding end of the baseplate of pulling unit, and therein at least one sub-plate is raised or dent with relative to other sub-plates so that all the sub-plates are not in the same plane in order to achieve overlapping connection by some sub-plates fitting in top face of corresponding branch plate and other sub-plates fitting in bottom face of corresponding branch plate. Then the raised head as in the above mentioned example wedges in the connecting hole of the branch plate or the screw passes through corresponding connecting hole and assembly hole to assemble. 
     In addition, in the present embodiment, a lug boss  2320  and a lug boss  2330  are respectively mounted on outer surfaces of the left erect plate  232  and the right erect plate  233 , vertical distance between the outer surface of the lug boss  2320  of the left erect plate and the outer surface of the lug boss  2330  of the right erect plate are identical with vertical width of the upper track. Preferably, both lug bosses are cuboid. For assembling, the pulling unit with double plates  20  are assembled upside down in the upper track with the baseplate of elastic unit  231  pressing against bottom of the upper track, and the lug bosses  2320 ,  2330  mentioned above respectively press against left and right sides of the upper track so that the pulling unit can be moved easily because of the structure of lug boss in need of adjusting position of the pulling unit  20  in the upper track. 
     Method to assemble the pulling unit with double plates in the upper track will be introduced next. First, mount the pulling unit with double plates  20  far from side of the door frame as possible when assembling the pulling unit with double plates  20  upside down in the upper track B, as final position thereof is not confirmed now. The pulling pillar  221  of the pulling unit with double plates  20  does not contact the damper sliding unit  15  of the anti-jumping upper wheel assembly with double dampers  10  when the door leaf A is being pulled from side to middle of the door frame, and then when the door leaf A is moved on from middle to the other side of the door frame the damper sliding unit  15  of the upper wheel assembly with double dampers  10  will contact the pulling pillar  221  and pull the pulling unit with double plates  20  toward the side of the door frame until reach it, and the pulling unit with double plates  20  is located voluntarily at this position. Then we can screw the internal hex stud  212  by hex s-screwdriver to press the internal hex stud  212  against top of the upper track and thus fix the pulling unit with double plates  20 . 
     Action mechanism of the anti-jumping upper wheel device with double dampers of the present invention will be introduced next. 
     Referring to  FIG. 22 , when the door leaf A is at side of the door frame, the pulling pillar  22  of the pulling unit with double plates  20  in the upper track B is plugged in the plugging hole  150  of the damper sliding unit  15  of the upper wheel assembly with double dampers  10 , when the door leaf A is being pulled from right to left the pulling pillar  221  pulls the damper sliding unit  15  to make the damper “strung” and then the door leaf A moves on to left, the pulling pillar  221  get out of the damper sliding unit  15  and the door leaf A slides free. When the door leaf A is being pushed from left to right as it is being closed, the pulling pillar  221  collides with the damper sliding unit  15  and makes the damper sliding unit  15  “unhooked” when the upper wheel assembly with double dampers  10  slides to below of the pulling unit with double plates  20 , and at this time the dampers of the upper wheel assembly with double dampers  10  functions to force the door leaf on reverse direction, the door leaf A will thus move smoothly without jumping and collision to reach edge of the door frame safely. 
     Advantages of the anti-jumping upper wheel device with double dampers of the present example are as follows: (i) it is novel in design and is proper structured; (ii) height of the pulling pillar can be adjusted; (iii) it can be assembled easily: because the connecting elastic unit is mounted at both sides of the baseplate of pulling unit of the pulling unit with double plates, which is made of material with high elasticity and which has cuboid lug bosses on the left and the right erect plates, the pulling unit with double plates thus can be assembled in the upper track with the connecting elastic unit pressing against both inner surface of the upper track steadily without falling off, and can also be pulled and pushed to move in the upper track; (iv) position of the pulling unit with double plates can be located voluntarily without manual work because of the improved structure of the baseplate of pulling unit; and (v) the anti-jumping upper wheel with double dampers has function of damping and anti-jumping. 
     The above mentioned is only preferred examples of the present invention and is not intended to limit protection coverage of the present invention, and any equivalent transformation and substitution of the technical solution of the present invention is in the protection coverage of the present invention.