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This application is the national stage of PCT/DE2004/00427 filed on Nov. 3, 2004 and claims Paris Convention priority of DE 103 51 255.1 filed Nov. 3, 2003. 
   The invention concerns a lowering device for a support structure for safely lowering all building industry loads. 
   Support structures for the building industry, such as ceiling formwork elements or floor tables are conventionally held by construction supports with adjustable length, which are adjusted to a predetermined length for a concrete pouring process. For example, a large number of construction supports, e.g. floor tables, are used for concrete pouring of large ceiling sections. When the ceiling to be poured with concrete has hardened to a sufficient degree, the formwork must be removed from the ceiling by shortening e.g. all telescopic construction supports which support the ceiling formwork until the formwork elements or floor tables can be removed and re-used at another location. 
   The removal of the formwork may be complicated when a plurality of construction supports are used to support heavy loads. Each construction support must be individually shortened, e.g. via a spindle procedure. 
   It is the object of the invention to provide a lowering device which can be moved in a safe, simple and rapid manner into a first working position and a second lowered position. 
   SUMMARY OF THE INVENTION 
   This object is achieved in accordance with the invention by a lowering device of a support structure, consisting of at least one plate, wherein a locking mechanism is formed on a first side of the plate, which can be moved into two positions, and wherein a support structure can be disposed at a second side of the plate, lifted relative to the stationary plate in a first position of the locking mechanism, and lowered relative to the stationary plate in a second position of the locking mechanism in response to the force of gravity, wherein the support structure engages the locking mechanism via at least one bolt, the bolt being displaceable relative to the plate from the first position into the second position and vice versa. 
   The inventive lowering device offers the essential advantage that a support structure can be adjusted to a required height by opening a locking mechanism which is stable under load and which automatically repositions itself, such that a support structure connected to the lowering device is immediately lowered by the desired amount. The lever ratios of the locking mechanism may thereby be selected such that even heavy loads of between e.g. 5 and 10 t can be lowered in a fast and safe manner by one worker using only little force. In its first position, the locking mechanism is self-locking under load, such that inadvertent opening of the inventive locking mechanism is not possible. 
   The inventive locking mechanism is preferably formed by one first and one second latch part which each surround at least part of a bolt at a first free end region thereof, wherein the bolts extend through elongated holes in the plate to permit displacement thereof relative to the plate, and the bolts can be fixed to the support structure in the region of their second free ends. 
   Safe lowering can thereby be advantageously ensured with a very simple structure. 
   In a further embodiment of the inventive locking mechanism, the second latch part is disposed for rotation around the bolt which it surrounds, and comprises a first and a second support surface via which the second latch part is supported on a projection of the plate in correspondence with its respective position, wherein the respective support surfaces have different separations from the axis of rotation formed by the bolt. 
   When the plate is stationary, this structure permits safe lowering of the support structure connected to the lowering device in dependence on the design of the two support surfaces of the second latch part and their separation from the axis of rotation of the second latch part. Lowering is possible only to the extent allowed by the matching support surfaces on the second latch part. 
   The first latch part advantageously comprises a first free end which partially covers an opening of the plate and surrounds the bolt in such a manner that, upon pivoting of the first latch part away from the opening, the second latch part automatically pivots into the second position under the action of the force exerted by the support structure onto the locking mechanism. 
   This is advantageous in that the locking mechanism can be triggered, i.e. be opened with only little force using an aid, e.g. a rod that can be inserted into the opening. The latch parts formed in the locking mechanism are pivoted and turned into a second end position, which limits the lowering motion of a support structure connected to the lowering device. 
   The inventive lowering device is further improved by mounting the plate to one end of a longitudinal housing having a bracket at the other end that has an elongated hole for receiving a bolt which can be connected to the support structure in a stationary manner, the bracket being overlapped by a frame which is rigidly connected to both the bracket and the plate. 
   This embodiment of the inventive lowering device permits connection of a conventional construction support to the lowering device in a torsion-proof and bending-resistant fashion. If the lowering device is mounted to a construction support in this fashion, the support structure connected to the lowering device can be lowered rapidly and safely by an amount predetermined by the locking mechanism. 
   The frame advantageously forms a housing which receives both the bracket and the plate, and comprises receptacles for a support for immovably connecting the lowering device to the support. A construction support can be quickly and safely mounted to the lowering device via such receptacles. 
   Lowering devices of this type are preferably mounted to the sides of truss girders of a floor table. If a floor table is held by numerous construction supports, each having an inventive lowering device, the floor table can be quickly and safely lowered and be re-used when the concrete pouring process is completed. 
   Further advantages can be extracted from the description of the attached drawings. The features of the invention mentioned above and below can be used individually or in arbitrary combination. The above-mentioned embodiments are not to be understood as exhaustive enumeration but have exemplary character. 
   The invention is described in more detail below with reference to an embodiment. The lowering devices or parts thereof shown in the figures are not necessarily true to scale. 

   
     BRIEF DESCRIPTION OF THE DRAWING 
       FIG. 1  shows an inventive lowering device which can be mounted e.g. to a support structure and to a construction support; 
       FIGS. 2   a  through  2   c  show different views of the inventive lowering device of  FIG. 1 ; 
       FIG. 3  shows a detail of an inventive lowering device comprising a locking mechanism formed in the lower part of the lowering device and located in a first position; 
       FIG. 4  shows a view of the locking mechanism of  FIG. 3  in a second position; 
       FIG. 5  shows inventive lowering devices which can be mounted to a truss girder; and 
       FIG. 6  shows inventive lowering devices with construction supports which are held in the lowering devices to secure a support structure, e.g. a truss girder, via the lowering devices. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1  shows a lowering device  10  which can be mounted to a construction support (not shown) and to a support structure (also not shown in the figure). The lowering device  10  is connected to a support structure via bolts  11 ,  12 ,  13 . The sections of the bolts  11 ,  12 ,  13  facing away from the support structure penetrate through a first elongated hole  14  and a second elongated hole  15  of the lowering device  10 . The bolts  11 ,  12 ,  13  and the support structure connected thereto can be displaced along the elongated holes  14 ,  15  when a locking mechanism  16  of the lowering device  10  is opened. 
   The locking mechanism  16  comprises a plate  17  with a projection or stop  18 , a first latch part  19 , a second latch part  20  and the bolts  12 ,  13 . The first and second latch parts  19 ,  20  can be pivoted or turned about the bolts  12 ,  13 . The second latch part  20  is supported on the projection  18  both in a first and in a second location of the locking mechanism  16 .  FIG. 1  shows the locking mechanism  16  in its closed position, i.e. a support structure connected to the bolts  11 ,  12 ,  13  is in the lifted position. 
   The bolt  11  is displaceably held in a bracket  21  which also contains the elongated hole  14 . The bracket  21 , which is bent in an L-shape, abuts the support structure to be retained, via a first leg piece  22 . A frame portion  24  is preferably connected to a second leg piece  23  of the bracket  21  with material fit. The frame  24  with bracket  21  and plate  17  and the individual parts mounted thereto, form a housing extending in a longitudinal direction, which also has a first and a second receptacle  25 ,  26  for guiding and fixing a construction support and which can preferably be adjusted in height. 
   The first receptacle  25  engages with a construction support held in this receptacle  25  in a positive fashion, and the second receptacle  26  is designed as finger that engages in the free end of a construction support. A construction support retained in the lowering device  10  can be securely connected to the lowering device  10 , e.g. via a bolt, through the opening formed on the finger. 
   The lowering device  10  of the figure is preferably a metal construction which can accept the load or a partial load of a support structure connected to the lowering device  10 . 
     FIGS. 2   a ,  2   b  and  2   c  show different views of the lowering device  10 .  FIG. 2   a  shows a side view of the lowering device  10  and the positions of the bolts  11 ,  12 , and  13 . The bolt  11  is disposed in the bracket  21  such that it can be displaced, and the bracket  21  also holds the receptacle  26  for fixing a construction support in the lowering device  10 . The bracket  21  is connected to the plate  17  holding the bolts  12 ,  13  via the frame  24 . The lower end of the frame  24  comprises the first receptacle  25 . 
     FIG. 2   b  shows the lowering device  10  in a positioned turned relative to  FIG. 2   a  such that the position and design of the bolts  11 ,  12 ,  13  and the design of the receptacles  25 ,  26  on the bracket  21  and on the lower end of the frame  24  are clearly shown. The locking mechanism formed in the lowering device  10  is covered by a cover plate  27  which protects the moved parts of the locking mechanism from being soiled and damaged. 
     FIG. 2   c  shows the lowering device  10  from a point of view which clearly shows the bearing of the bolt  11  in the bracket  21  and the bearing of the bolts  12 ,  13  in the plate  17 . The receptacle  25  and the bracket  21  project beyond the frame  24 . The bolts  11 ,  12 ,  13  are displaceably disposed in the elongated holes  14 ,  15 . The plate  17  has an opening  28  via which the locking mechanism formed on the other side of the plate  17  can be actuated. In a state of the lowering device  10  mounted to a support structure, the opening  28  must be accessible for the staff operating the lowering device  10 . The bolt  11  can be displaced in the elongated hole  14  in the direction of arrows  29  and the bolts  12 ,  13  can be displaced in the elongated hole  15  in the direction of arrows  30 . When a support structure is mounted to the bolts  11 ,  12 ,  13 , the bolts  11 ,  12 ,  13  can be displaced in the direction of arrows  29 ,  30  with the lowering device being stationary. 
     FIG. 3  shows a detail of the frame  24  with plate  17  mounted thereto, which receives the locking mechanism  16 . The first receptacle  25  projects beyond the plate  17  and the projection  18  which supports the second latch part  20  via a first support surface  31  lies in front of the plane formed by the plate  17 . The support surface  31  is supported on a stop surface  32  of the projection  18 . The first and second latch parts  19 ,  20  are designed and matched to each other such that the locking mechanism  16  is safely and immovably held in its self-locking position shown in the figure even when the lowering device  10  is subjected to heavy loads by a support structure. When the bolts  12 ,  13  are each rigidly connected to a support structure, and the locking mechanism  16  is stationarily mounted to a construction support, the locking mechanism  16  retains the support structure, fastened via the bolts  12 ,  13 , in a lifted first position. A vertical load acting directly on the bolts  12 ,  13  cannot change the position of the locking mechanism  16 . In the first location of the locking mechanism  16 , a free end  33  of the first latch part  19  partially covers the opening  28  formed on the plate  17 . If the closed locking mechanism  16  shown in  FIG. 3  is opened by a force acting on the free end  33  of the first latch part  19 , by introducing a force in an anticlockwise direction onto the free end  33 , the first and the second latch part  19 ,  20  move. The first latch part  19  can be turned about an axis of rotation  34  and the second latch part  20  is disposed to be rotatable about an axis  35  of the bolt  13 . If the first latch part  19  is loaded about the axis of rotation  34  in an anticlockwise direction via the first free end  33 , the first latch part  19  pivots away from the bolt  12  and the second latch part  20  simultaneously turns about the axis  35  of the bolt  13  in a clockwise direction. As the second latch part  20  turns in a clockwise direction, the bolts  12 ,  13  move from a raised position ( FIG. 3 ) into a lower position within the elongated hole  15 . 
     FIG. 4  shows the locking mechanism  16  of the inventive lowering device in an open second position. In the second position of  FIG. 4 , the bolts  12 ,  13  are moved downwards in the longitudinal hole  15  and the plate  17  is stationary. The first latch part  19  is pivoted in a counter clockwise direction about the axis of rotation  34  via the free end  33  e.g. by pushing a rod from behind through the plate  17  into the opening  28 , thereby triggering a turning motion of the second latch part  20  in a clockwise direction such that a second support surface  36  of the second latch part  20  abuts the support surface  32 . During this rotation about the axis  35 , the bolt  13 , which is rotatably disposed in the second latch part  20 , as well as the bolt  12  are lowered. The axis of rotation  34  is lifted during this motion sequence. In the second position, the free end  33  of the first latch part  19  frees the opening  28 . When the bolts  12 ,  13  move into the position shown in  FIG. 4 , a support structure connected to the bolts  12 ,  13  is also lowered with the plate  17  remaining stationary. 
     FIG. 4  also shows how the receptacle  25  may be formed on the plate  17 . The projection  18  is mounted or formed in the angled region of the plate  17  facing the receptacle  25 . The size of the latch parts  19 ,  20  and the height of the projection  18  are adjusted such that the locking mechanism  16  can assume the second position on the plate  17  shown in this figure as well as the first position shown in  FIG. 3 . 
     FIG. 5  shows three lowering devices  10  which can be mounted e.g. on a support structure such as a truss girder. Three lowering devices  10  are mounted to vertical struts  37  of a truss girder  38  by securely mounting the brackets  21 , at one end of the respective lowering device  10 , and the plates  17 , at the other end of the respective lowering device  10 , to the truss girders  38  using bolts. The bolts connecting the support structure to the lowering device  10  are guided in elongated holes of the lowering devices  10  in such a manner that they can be moved to different positions depending on the position of the locking mechanism formed in the lowering devices  10 . Construction supports of any outer shape can be inserted into the receptacles  25 ,  26 . The receptacles  25 ,  26  are designed in dependence on the outer shape and the properties of the respective construction supports. 
     FIG. 6  shows three lowering devices  10  including construction supports  39  introduced into the lowering devices  10 , as they are mounted to the truss girder  38 . The construction supports  39  retain the support structure mounted to the lowering device  10  at a predetermined height relative to the ground on which the ends of the construction supports  39  seat. The other ends of the construction supports  39  engage the lowering device  10  and are supported on the inner side of the brackets  21 . The frames  24  of the lowering devices  10  which connect the brackets  21  to the lower mounting points of the lowering device  10  are designed to hold a support structure, such as the truss girder shown in the figure, in a torsion-proof and bending-resistant fashion. If the construction supports  39  are aligned at a certain level and fixed to the lowering devices  10 , the locking mechanisms formed in the lowering devices  10  can lower the support structure mounted to the lowering devices  10  by moving the locking mechanisms  16  from the first position into the second position. If the support structure is e.g. lifted via aids such as a crane, the locking mechanisms  16  of the individual lowering devices  10  automatically move back into the first position. The latch parts of the locking mechanisms  16  are designed such that they always automatically pivot or turn into the first location when the load is removed. 
   A lowering device  10  of a support structure for the construction industry comprises at least one plate  17  which holds a locking mechanism  16  and either blocks the motion of the bolts  12 ,  13  or releases that blockage. The bolts  12 ,  13  are rigidly connected to a support structure and are also held in the locking mechanism  16  in a controlled manner, such that the support structure connected to the lowering device  10  is lifted in a first position and the support structure connected to the locking mechanism is lowered in the second position thereof to the extent permitted by the locking mechanism.

Summary:
The invention relates to a lowering device ( 10 ) for the construction industry, which comprises a support structure. The lowering device comprises a plate ( 17 ) holding a locking mechanism ( 16 ) and blocking or releasing the mobility of bolts ( 12, 13 ). The bolts ( 12, 13 ) are firmly linked with a support structure and are fastened on the locking mechanism ( 16 ) in a controlled manner to such an extent that, in a first position, the support structure linked with the lowering device ( 10 ) is lifted and, in a second position of the locking mechanism, the support structure linked therewith is lowered as much as the locking mechanism permits.