Patent Publication Number: US-8109040-B2

Title: Linear drive arrangement for a sliding door

Description:
PRIORITY CLAIM 
     This is a U.S. national stage of application No. PCT/EP2003/013872, filed on 8 Dec. 2003. Priority under 35 U.S.C. §119(a) and 35 U.S.C. §365(b) is claimed from German Application No. 102 57 582.7, filed 9 Dec. 2002. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention is directed to a stabilizing arrangement for a guide carriage, particularly for a sliding door or the like which is movable by a linear drive, wherein the sliding leaf is suspended by magnetic forces. 
     2. Description of the Related Art 
     A common problem in sliding doors that are moved by a linear drive consists in that the sliding door executes a shaking or rocking motion when starting and when braking similar to a motor vehicle during acceleration and braking. This rocking motion occurs when starting due to the inertial forces of the door leaf and the acceleration forces of the stationary stator of the linear drive. The acceleration forces tend to displace the leaf laterally and the inertial forces oppose this tendency. This process takes place in an analogous way in reverse when braking. A special situation arises when the door leaf must reverse due to an obstruction. This impairs normal operation of the sliding door. 
     U.S. Pat. No. 5,712,516 describes a linear drive for a sliding door. In this drive, a stationary long-stator is located above the movable leaf. The individual coils are distributed along the entire length of the stator, namely, in an equally spaced manner. The yoke of the stator comprises bars disposed transverse to a longitudinally arranged yoke part. The side of the transversely arranged yoke segments that faces the leaf is connected by a ferromagnetic plate to spacer strips arranged thereon. Permanent magnets are located on the movable leaf. When the movable leaf is fixed to the plate described above, the leaf is suspended at the stator due to the magnetic force of the permanent magnets. Due to the presence of spacer rollers at the end and at the beginning of the displaceable leaf, there is a defined air gap between the permanent magnets and the spacer strips or plate. When current is supplied to the coils, the magnetic field thereby generated inside the stator is advanced so that the suspended door can continue moving. 
     SUMMARY OF THE INVENTION 
     Therefore, it is the object of the present invention to provide a stabilizing arrangement which prevents the rocking motion of the sliding door, particularly when starting and braking. 
     The rocking motion occurring just at the start and end of the movement process of the sliding door can be reliably prevented by providing the guide carriage with at least one supporting roller which is supported at least at times on a guide track. 
     According to an advantageous embodiment form, a supporting roller is provided, respectively, in the front end area and rear end area of the guide carriage in order to achieve the most efficient possible stabilization of the sliding door. 
     The two supporting rollers are preferably arranged on the same side of the guide carriage. This has the advantage that the two supporting rollers can roll on the same guide track. 
     According to an advantageous further development, the supporting rollers have a bearing shaft which penetrates the guide carriage in a bore hole in order to arrange the supporting rollers so as to be accurately positioned at the guide carriage. 
     To enable an exact adjustment of the guide roller with respect to the guide track and so that the guide roller rolls on the guide track with as little friction as possible, a freely rotatable roller running on the guide track is arranged, according to the invention, at one end of the bearing shaft eccentric to the shaft axis. 
     According to an advantageous embodiment form, a thread serving to receive a fastening screw is arranged at the end of the bearing shaft opposite to the roller for a reliable fastening of the bearing shaft. In this way, the bearing shaft can engage through the guide carriage so that the guide carriage can be guided with precision and without play. 
     According to an advantageous further development, the roller is detachably arranged at the bearing shaft so that the roller can easily be exchanged in case of wear. 
     To permanently prevent a rocking motion of the sliding door by means of a permanent support of the guide rail at the guide track, it can be provided according to the invention that the roller rolls on the guide track during the entire movement process of the sliding door. 
     However, if the entire movement of the guide carriage should take place with as little friction as possible, the roller, according to an alternative embodiment form, can also have a slight distance from the guide track and can roll on the guide track only during the start phase and end phase of the movement process of the sliding door. The slight distance can be compensated by a slight rocking motion of the sliding door. Depending upon the selected distance, even a barely perceptible rocking motion can be sufficient to overcome the distance. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows an overall view of a linear drive according to the invention; 
         FIG. 2  shows a guide carriage used in combination with the linear drive according to the invention for the suspension of a sliding door; 
         FIG. 3  is a perspective view of a holder used in the guide carriage according to the invention; 
         FIG. 4  is a front view of the holder of  FIG. 3 ; 
         FIG. 5  is a side view of the holder of  FIG. 3 ; 
         FIG. 6  is a top view of the holder of  FIG. 3 ; 
         FIG. 7  shows a construction variant of the holder; 
         FIG. 8  shows another construction variant of the holder; 
         FIG. 9  is a top view of the guide carriage according to  FIG. 3 ; 
         FIG. 10  shows the holder according to  FIG. 3  in connection with a sliding door; 
         FIG. 11  shows the holder according to  FIG. 4  with an additional height adjustment; 
         FIG. 12  shows a construction variant of the holder in connection with a sliding door; 
         FIG. 13  shows another construction variant of the holder in connection with a sliding door; 
         FIG. 14  shows a supporting rail used in connection with the linear drive according to the invention; 
         FIG. 15  is a perspective view of a shoe of a first embodiment of an aligning device for a sliding door; 
         FIG. 16  is a perspective view of a shaft of the first embodiment of the aligning device; 
         FIG. 17  is a perspective view of a swiveling arm of the first embodiment of the aligning device; 
         FIG. 18  shows a supporting rail according to another embodiment form used in connection with the linear drive according to the invention; 
         FIG. 19  is a perspective view of a support of a second embodiment of the aligning device; 
         FIG. 20  is another perspective view of the support; 
         FIG. 21  is a perspective view of a shaft of the second embodiment of the aligning device; 
         FIG. 22  shows an embodiment form of the coils used in the linear drive according to the invention; 
         FIG. 23  is a bottom view of the linear drive according to the invention; and 
         FIG. 24  shows a detail from a sliding door stabilizing arrangement used in connection with the linear drive according to the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS 
       FIG. 1  shows an overall view of a linear drive  1  according to the invention. The linear drive  1  is accommodated in a holder  2  (see  FIG. 23 ) which can be fastened to a building part (not shown). The linear drive  1  itself comprises a stationary guide rail  3  mounted in the holder  2  and a guide carriage  4  which is displaceable in the guide rail  3 . A sliding door  5  (see  FIG. 10 ) which is movable in longitudinal direction of the guide rail  3  is mounted at the guide carriage  4 . The guide carriage  4  is shown in detail in  FIG. 2 . 
     The guide rail  3  has C-shaped slide rails  6  which are spaced apart with their open sides facing away from one another. A portion of the guide carriage  4  is located between the slide rails  6 . Coils  7  are arranged in the oppositely facing open sides of the C-shaped slide rails  6  and can be inserted therein from the end sides of the slide rails  6 . The coils  7 , shown in detail in  FIG. 22 , are connected to a contact rail  8 . Further, an aligning device  9  is provided at the guide carriage  4 ; the sliding door  5  connected to the guide carriage  4  can be aligned by means of this aligning device  9 . 
       FIG. 2  shows the guide carriage  4  in detail. The guide carriage  4  has a supporting rail  10  which is formed as a hollow box section. A C-shaped channel  11  (see  FIG. 14 ) which extends centrally in longitudinal direction of the supporting rail  10  and opens upward is formed on the upper side of the hollow box section. A holding member  12  which can be inserted into the supporting rail  10  from the end side can be inserted in this channel  11 . Magnets  13  are received in this holding member  12  and, together with the coils  7  mounted at the C-shaped slide rails  6 , form a holder and a drive for the sliding door  5 . The construction of the holding member  12  is described more fully in connection with  FIGS. 3 to 8 . 
     Further, the aligning device  9  is provided at the respective ends of the supporting rail  10 . The sliding door  5  can be aligned with respect to the supporting rail  10  by means of this aligning device  9 . The aligning device  9  will be described in more detail later in connection with  FIGS. 14 to 17 . 
     The holding member  12  comprises a plurality of individual holders  14 .  FIG. 3  shows an individual holder  14  of this type. The holder  14  has a base  15  which can be inserted into the C-shaped channel  11  at the supporting rail  10 . The base  15  is provided at its front end with a connection element  16  and at its rear end with a connection element  116  which makes it possible to connect a plurality of individual holders  14  to one another in order to form the holding member  12 . In the present embodiment example, the connection elements  16  which are constructed in a complementary manner comprise a partially circular locking receptacle  116  at one end and a partially circular locking projection  16  at the other end. The locking projection  16  is inserted into the locking receptacle  116  in such a way that the individual holders  14  are swivelable relative to one another in the plane of the base  15  in order to compensate for tolerances. The connection elements  16  can be inserted in the elements  116  either in vertical direction or in horizontal direction. To enable insertion in the horizontal direction, the connection elements  16  are formed elastically so that the partially circular projection  16  is compressed by a corresponding wedge-shaped insertion ramp at the partially circular locking receptacle  116 . 
     A receptacle  17  serving to support the magnets  13  extends upward from the base  15 . The receptacle  17  is shorter than the base  15  so that a space is formed between the individual receptacles  17  when a plurality of holders  14  are joined. Further, each receptacle  17  has two channel-shaped pockets  18  which are arranged on opposite ends of the receptacle  17 . The magnets  13  can be inserted into these channel-shaped pockets  18  in such a way that they bridge the distance between two receptacles  17  as is shown in  FIG. 2 . Vertically extending strips  19  which serve to guide the holders  14  at the inner sides of the slide rails  6  are provided on the outer sides of the receptacles  17 . These strips  19  either have a slight air gap relative to the slide rails  6 , e.g., 0.1 mm, or contact the slide rails  6  directly without an air gap. 
     Construction variants of the holder are shown in  FIGS. 7 and 8 .  FIG. 7  shows a holder  14 ′ which is inserted into the supporting rail  10  as an end piece and which, for this reason, is provided with a pocket  18  on only one end, while the end shown in  FIG. 7  is planar, i.e., formed without a pocket. 
     When building the holding member  12 , the holder  14 ′ shown in  FIG. 7  is first inserted, as initial holder, into the channel  11  of the supporting rail  10 . A magnet  13  is then inserted by its front end into the pocket  18  of the first holder  14 ′. A holder  14  which is shown, e.g., in  FIG. 4 , is subsequently inserted into the channel  11 . In so doing, the pocket  18  facing forward receives the rear end of the first magnet  13 . A magnet  13  is now inserted again by its front end into the rear pocket  18  of the next holder  14 . This is followed by another holder, and so on, until the supporting rail  10  is completely filled with holders  14  and magnets  13 . Finally, a holder  14 ′ according to  FIG. 7  is then inserted again into the supporting rail  10 . The supporting rail  12  is now in the form shown in  FIG. 2 . 
       FIG. 8  shows an entirely different holder  14 ″ in which the base  15  is not shown for reasons of simplicity. This holder  14 ″ has an H-shaped construction as seen from the top and the pockets  18 ″ open upward. Accordingly, all of the holders  14 ″ can be inserted in the supporting rail  10  one behind the other. The magnets  13  are then inserted from above into the pockets  18 ″ of the holders  14 ″ and the pockets  18 ″ are finally closed by a cover  20  (see  FIGS. 12 and 13 ) which preferably covers a plurality of pockets  18 ″ or inserts  22 . 
       FIG. 9  is a top view showing the holding member  12  comprising a plurality of holders  14  and magnets  13 . It will be seen that the bases  15  contact one another, while the receptacles  17  are spaced apart. This space is bridged by the magnets  13  which rest in the pockets  18  of the receptacles  17 . The strips  19  arranged laterally at the receptacles  17  contact the inner sides of the slide rails  6  so as to be substantially free from play and guide the holding member  12  in the slide rails  6 . 
       FIG. 10  shows a side view of the holding member  12  in connection with the sliding door  5 , this holding member  12  comprising a plurality of holders  14  and magnets  13 . The holding member  12  is directly connected to the sliding door  5 . When height compensation is required, the holding member  12  can also be connected to the sliding door  5  with the intermediary of spacer strips  21  as is shown in  FIG. 11 . 
       FIG. 12  shows a side view of the holding member  12 ″ comprising holders  14 ″ according to  FIG. 8  in connection with the sliding door  5 . The magnets  13  are inserted into the pockets  18 ″ from above and are secured by the cover  20 . The cover  20  is connected to the receptacles  17 ″ by means of connection elements, not shown in detail. 
       FIG. 13  shows a side view of another embodiment form of the holding member  12 ′″ in connection with the sliding door  5 . The holding member  12 ′″ shown in this case comprises holders  14 ′″, each of which has a plurality of inserts  22  which open upward and in which the magnets  13  can be inserted. In this case also, the inserts  22  are closed by a cover  20 . Another difference with respect to the holders  14 ,  14 ″ shown in  FIGS. 10 to 12  is that the magnets  13  in the holders  14 ,  14 ″ according to  FIGS. 10 to 12  are open toward the side, i.e., toward the slide rails  6 , while the magnets  13  in the holder  14 ″″ according to  FIG. 13  are also enclosed toward the side by the holder  14 ″″ and side walls of the inserts  22 . 
       FIGS. 14 to 17  show the individual parts of an aligning device  9  which is preferably constructed as an eccentric adjustment and by means of which the sliding door  5  connected to the supporting rail  10  can be aligned. For this purpose, a series of transverse through-holes  23  are arranged in the respective end portions of the supporting rail  10 . 
     Also belonging to the aligning device  9  is a shoe  24  which has two vertically oriented plates  25  making contact with the lateral surfaces of the supporting rail  10  and a horizontally oriented fastening plate  26  connecting the two plates  25  at one of their ends. A number of aligning slots  27  corresponding to the number of through-holes  23  in the supporting rail  10  is provided in the plates  25 . The two outer aligning slots  27  are formed as vertically extending elongated holes, while the center aligning slot  27  has a horizontal T shape. A transverse slot  28  in the fastening plate  26  serves to receive a connection element, not shown, for attaching the sliding door  5 . 
     Also belonging to the aligning device  9  is a shaft  29  having a circular cross section in its central area and a square  30  at both ends (see  FIG. 16 ) and a swiveling arm  31  shown in  FIG. 17 . The swiveling arm  31  has a [receiving] square opening  32  for receiving the square  30  and a cam  33  formed in the present embodiment with a hexagon socket. 
     The aligning device  9  which comprises the supporting rail  10 , the shoe  24 , the shaft  29  and the swiveling arm  31  and which is shown in its entirety in  FIG. 2  is constructed in the following manner. 
     The shoe  24  is slid onto the supporting rail  10  in such a way that the through-holes  23  in the supporting rail  10  are aligned with the aligning slots  27 . The shaft  29  is then inserted through the center aligning slot  27 , formed as a horizontal T, such that it lies in the area of a vertical arm of the T. The squares  30  formed at the two ends of the shaft  29  project beyond the plates  25 . A swiveling arm  31  is now inserted on each square  30  and fastened by a retaining screw  34  in such a way that the cam  33  faces inward and engages in the horizontal arm of the horizontal T. Finally, locking bolts  35  are inserted and engage through the two outer aligning slots  27  and the outer through-holes  23 . 
     The relative position of the shoe  24  can now be adjusted with respect to the supporting rail  10  by rotating the shaft  29  and the swiveling arm  31  fastened to the shaft  29 , so that the sliding door  5  can be aligned with respect to its position relative to the guide carriage  4 . After alignment, the locking bolts  35  are tightened so that the position can no longer be changed once it has been adjusted. 
     Another embodiment form of the supporting rail  10 ′ is shown in  FIG. 18 . This supporting rail  10 ′ has a partially circular longitudinal channel  36  which extends centrally and in which the correspondingly shaped base of the holder  14  can be inserted. 
       FIGS. 19 to 21  show another embodiment form of the aligning device  9  which is likewise preferably constructed as an eccentric adjustment and which can be used particularly with the supporting rail  10 ′ according to  FIG. 18 . This aligning device  9  is not arranged laterally at the supporting rail  10 ′ as is the aligning device  9  according to  FIGS. 15 to 17 , but rather at the side of the supporting rail  10 ′. The aligning device  9  has an L-shaped angle support  37  that can be arranged at the front side of the supporting rail  10 ′ and an eccentric shaft  38  associated with each angle support  37 . A leg  39  of the angle support  37  has two transverse slots  40  which serve to fasten the sliding door  5  arranged at the angle support  37 . Another leg  41  of the angle support  37  which is wider than the leg  39  and which projects beyond the sides of the latter has two vertical slots  42  in the projecting area which extend transverse to this leg  41  and which serve to connect to the side of the supporting rail  10 ′. Further, a vertical slot  43  which opens toward one side is provided in the middle between the two elongated holes  42 . On the side remote of the leg  39 , a receiving channel  44  extending transverse to the slot  43  and to the slots  42  is arranged in the leg  41  and intersects the slot  43 . 
     The eccentric shaft  38  which also belongs to the aligning device  9  comprises a shaft stub  45 , an outwardly projecting cam  46  being arranged at one end of the shaft stub  45  by means of an eccentric arm. An engagement opening  47  which is formed as a hexagon socket in the present embodiment example is provided in the axis of the shaft stub  45  and is serves for adjusting the eccentric shaft  38  by means of a corresponding tool. 
     The aligning device  9  according to  FIGS. 18 to 21  is used in the following manner: The shaft stub  45  of the eccentric shaft  38  is inserted into the longitudinal channel  36  of the supporting rail  10 . The angle support  37  is then placed with its leg  41  against the supporting rail  10  in such a way that the cam  46  can engage in the receiving channel  44 . In this position, the engagement socket  47  can be reached through the slot  43 . In order to align the supporting rail  10  to the sliding door  5 , the eccentric shaft  38  is rotated by means of a tool of the like. In so doing, the shaft stub  45  rotates in the longitudinal channel  36  and the cam  46  slides into the receiving channel  44 . After alignment, fastening bolts arranged in the slots  42  are tightened. 
       FIG. 22  shows the coils  7  used in connection with the linear drive  1  according to the invention. The coils  7  are held in coil holders  48 . The coil holders  48  are provided with a base plate  49  by which they can be inserted into the C-shaped slide rails  6  (see  FIG. 1 ). Spacers  50  are provided between the coil holders  48  or coils  7  and likewise have a base plate  51  which is insertable into the C-shaped slide rails  6 . The spacers  50  are formed with different lengths so that the distances between the coils  7  can be varied. Naturally, the coils  7  and their coil holders  48  can also contact one another directly without the intermediary of spacers  50 . Further, connection lugs  52  are provided at the coils  7  for the electrical connection of the latter. 
     The coils  7  can either be inserted into the coil holders  48  in different positions or, according to an alternative construction, can also be received in the coil holders  48  so as to be rotatable around their axis so that the connection lugs  52  face in different directions depending on the position of the coil  7 . In the example shown in  FIG. 22 , the connection lugs  52  of one coil  7  face to the side, while the connection lugs  52  of the other coil face upward. As a result of this arrangement with connection lugs  52  which are preferably arranged so as to alternate by 90°, it is possible to polarize the coils differently depending upon the position of their connection lugs  52  when attaching the contact rail  8 . The ends of all of the connection lugs  52  face in the same direction so that no problems can result when the attaching the contact rail  8 . 
       FIG. 23  shows the linear drive  1 , according to the invention, in the assembled state with only the sliding door  5  arranged at the shoes  24  being omitted for the sake of clarity. It will be seen that the holding member  12  comprising individual holders  14  and magnets  13  is arranged between the two C-shaped slide rails  6  virtually without play. A series of coils  7  is inserted into the slide rails  6  on their outer side and, depending on the position of their connection lugs  52 , are connected to the upper or side contact leads arranged in the contact rail  8 . The sliding door  5  is held exclusively by the force generated by the coils  7  and the magnets  13  and moves forward or backward depending on the generated magnetic field. 
     It can also be seen from  FIG. 23  that a supporting roller  53 , shown in detail in  FIG. 24 , is arranged at the guide carriage  4  in the front area and rear area, respectively. These supporting rollers  53  stabilize the sliding door  5  when starting and braking and accordingly prevent a rocking motion of the sliding door  5 . The supporting rollers  53  are each journaled on a bearing shaft  54  which penetrates the supporting rail  10  in a bore hole  55  (see  FIG. 14 ). A freely rotatable roller  53  running on a guide track  57  of the holder  2  is arranged at one end of the bearing shaft  54  eccentric to the shaft axis (see  FIG. 23 ). A thread  56 ,  FIG. 2 , serving to receive a fastening nut  59  (see  FIG. 2 ), is arranged at the other end of the bearing shaft  54 . The roller  53  is preferably detachably arranged at the bearing shaft  54  so that the roller  53  can be exchanged easily if necessary. The supporting rollers  53  both lie on the same side of the supporting rail  10 . Due to the eccentric support of the roller  53  relative to the shaft axis, the roller  53  can be adjusted in its position by rotating the bearing shaft  54  and in this way can be exactly aligned with the guide track  57 . 
     It is not necessary that the supporting rollers  53  roll on the guide track  57  throughout the entire movement of the sliding door  4 . Rather, the rollers  53  can also have a slight distance, e.g., of a few tenths of a millimeter, from the guide track  57  because the sliding leaves of the sliding door  5  are suspended in a hovering state by means of the magnetic force of the magnets  13 . The hovering state is interrupted during starting and braking by the rocking motion of the sliding door  5 . Depending on the selected distance, even a barely perceptible rocking motion can be sufficient to overcome the distance. Accordingly, the rollers  53  would roll on the guide track  57  only in the acceleration phase and braking phase, while they are at a distance from the guide track  57  during the normal movement of the sliding door  5  and accordingly also do not cause any additional friction, since the sliding door  5  is also in a hovering state. 
     The preceding description of the embodiment examples of the present invention serves for purposes of illustration only and not to limit the invention. Various changes and modifications are possible within the framework of the invention without departing from the scope of the invention and its equivalents.