Patent Abstract:
A leveling device has a housing, a support surface which is fixed with the housing, an adjusting device including at least one adjusting screw which is displaceable outwardly and has an adjusting thread which is engageable with a counter thread for adjusting the adjusting screw, the counter thread being formed as a partially side of a slider which is displaceable transversely to a longitudinal axis of the adjusting screw and disengageable from the adjusting thread.

Full Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a leveling device. 
     Leveling devices are known in the art. One of such devices is disclosed for example in the U.S. Pat. No. 5,519,942. The leveling device of this patent has a housing, a support surface which is fixed to the housing, an adjusting device. The adjusting device has at least one adjusting screw which can be displaced so that it extends outwardly beyond the support surface. For this purpose the adjusting screw is provided with an adjusting thread which engages with a counter thread in the housing. The adjusting device with the adjusting screw serves for adjusting the leveling device to the desired leveling plane, which is adjustable by means of a water balance formed on the leveling device. This construction however has a substantial disadvantage that the adjusting screw must be screwed back when it must be again returned into the housing so that it no longer extends outwardly beyond the support surface. In the practice, the return points for the operators of the leveling device are frequently omitted, since it is too time consuming and complicated. When the adjusting screw after the use of the leveling device must again extend outwardly beyond the support plane of the support surface, the adjusting screw can be easily damaged. Moreover the leveling device with the extended adjusting screw can not be used as a water balance. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the present invention to provide a leveling device of the above mentioned type which avoids the disadvantages of the prior art. 
     In keeping with these objects and with others which will become apparent hereinafter, one feature of present invention resides, briefly stated in a leveling device, in which the counter thread engaging with an adjusting thread of the adjusting screw extending beyond the abutment surface is formed as a partial thread on a slider which is displaceable transversely to the longitudinal section of the adjusting screw and is bringable outside of engagement with the adjusting thread. 
     When the leveling device is designed in accordance with the present invention, it has the advantage that the adjusting screw can be returned in each arbitrary position in a simple manner in the housing of the leveling device, so that every time without great expenses the operation of a water balance is available. 
     In accordance with a further advantageous feature of the present invention, the adjusting screw after actuation of a releasing key is displaceable back by the spring force. Thereby the one-hand operability of the leveling device remains guaranteed. 
     The novel features which are considered as characteristic for the present invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a leveling device in accordance with the present invention; 
     FIG. 2 is a longitudinal section through the inventive leveling device; 
     FIG. 3 is a partial section through the inventive leveling device on an enlarged scale when compared with FIG. 2; 
     FIG. 4 is a cross-section through the inventive leveling device; and 
     FIG. 5 is a view of the leveling device in accordance with the present invention as seen from the front. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A leveling device in accordance with the present invention is identified with reference numeral  10  in FIG.  1 . It has a housing  11  which forms a support surface  13  on a lower side  12 . 
     The leveling device  10  has a level element  14  oriented parallel to the support surface  13 . Moreover, the leveling device  10  has a light indicating device  15 , which can produce a bundled light beam oriented parallel to the support surface  13 . Furthermore, an adjusting device  16  is provided for orienting the support surface  13  relative to the respective substrate, in particular horizontally. 
     The adjusting device  16  is further provided with two support legs  17   a  and  17   b . They are arranged laterally on the housing and turnable so that they can extend outwardly beyond the support surface  13  as shown in FIG.  5 . In FIG. 1 the support legs  17   a ,  17   b  are shown in their folded back position. The abutment legs  17   a ,  17   b  are substantially plate-shaped and have outwardly curved support edges  57   a  and  57   b.    
     In the leveling device  10  shown in FIG. 2 level element  14  extends parallel to the support surface  13 . In the front region  18  the leveling device has a light indicating device  15 . The light indicating device includes a laser diode  20 , a collimation lens  21  and a light outlet passage  22 . The path of rays of a light beam produced by the light indicating device  15  is oriented parallel to a longitudinal axis  23  of the leveling device  10 , to which also the support surface  13  is oriented parallel. 
     A battery compartment  26  is located substantially centrally in the housing  11  of the leveling device  10 . A battery  27  for the current supply of the light indicating device  15  is accommodated in the battery department  26 . The adjusting device  16  is accommodated in a rear region  19  of the leveling device  10  and has an adjusting screw  30  which is arranged substantially transversely to the longitudinal axis  23 . In FIG. 2 it is shown in a base position at the housing  11 , displaced back behind the support surface  13 . 
     The adjusting screw  30  has a cylindrical shaft part  31  which is provided on the outer periphery with an adjusting thread  36 , and also a multi-edge drive part  32 . The adjusting screw is form-lockingly coupled via the drive part  32  with an adjusting wheel  34 . The adjusting wheel  34  engages partially in the window retained laterally in the housing  11  through the housing  11  and therefore is available for actuation of the adjusting screw  30  by the operator from outside. At the end located near the support surface  13 , the adjusting screw  30  forms an adjusting mandrel  33 . 
     A slider  37  is supported displaceable transversely to the displacing direction of the adjusting screw  30  in the housing  11 . The slider  37  has a throughgoing opening  38 , through which the adjusting screw  30  engages with its shaft part  31 . The throughgoing opening  38  is wider than the diameter of the shaft part  31  of the adjusting screw  30 , so that the slider  37  is displaceable within certain limits. An inner thread  39  is formed on a wall of the throughgoing opening  38 . It is bringable in engagement with the adjusting thread  36 . The inner thread  39  is substantially semi circular and forms a partial thread. The slider  37  is pre-tensioned by a pressure spring  40  in the direction toward the engaging position of the inner thread  39  and the adjusting thread  36 . 
     In the arresting position shown in FIG. 2, the slider  37  is blocked by an arresting pin  41  which in this position serves as an abutment for the pretensioning force of the pressure spring  40 . The arresting pin  41  engages with its end  42  facing the support surface  13 , into the arresting opening  43  in the slider  37 . The arresting opening  43  has substantially the same diameter as the slider  37 , so that the slider  37  is blocked form-lockingly in the arresting position. In this position the inner thread  39  and the adjusting thread  36  are not in engagement with one another. Simultaneously the adjusting screw  30  is forced by a return spring  44  to a base position in which it is completely withdrawn into the housing. In this base position the support surface  13  is available for the support purposes. 
     A push button  48  is located in a rear region  19  of the leveling device  10 , in an extension of the arresting pin  41 . The arresting pin  41  is displaceable by the push button  48  from the base position relative to the slider  37 . Near a support-side end  42 , the arresting pin  41  is provided with a narrowing  49  which is displaceable by the pressing in of the push button  48  at the height of the arresting opening  43 . When the narrowing  49  and the slider  37  are in alignment with one another, the slider  37  is released axially, so that the slider  37  is displaced by the force of the spring  40 , until the inner thread  39  and the adjusting thread  36  are engaged with one another as shown in FIG.  3 . Simultaneously, a first spring  50  is pre-tensioned and loads the push button  48 . After releasing of the push button  48 , the first spring  50  forces the push button  48  again back to its initial position, and the projections  52 ,  53  of the push button  48  come to abutment against the corresponding projections on the housing  13 . A second spring  51  loads the arresting pin  41  with its return force. 
     FIG. 3 shows the rear region  19  of the adjusting device  16  in its adjusting position, on a scale which is enlarged when compared with FIG.  2 . In this position the thread  36  on the shaft part  11  of the adjusting screw  30  is in engagement with the inner thread  39  on the slider  37 . The slider  37  engages on the one hand in the narrowing  49  in the arresting pin  41 . In this engaging position, the adjusting screw  30  by turning of the adjusting wheel  34  displaces as a result the thread connection  36 / 39  against the restoring spring  44 , and the abutment mandrel  33  then extends outwardly of the housing  11  and is displaceable outwardly over the support surface  13 . 
     On its end which faces away from the slider  37 , its pressure spring  40  has a T-shaped actuation button  54  which extends outwardly of the housing  11 . Therefore, the actuation button  54  is accessible for the operator of the inventive machine  10 . By pressing the actuating button  54 , the operator can displace the slider  37  against the pretensioning force of the pressure spring  40 , and the slider is moved back from the narrowing  49  and releases in this way the arresting pin  41 . The arresting pin  41  is displaced again to its initial position shown in FIG.  2 . The inner thread  39  and the adjusting thread  36  then again engage one another. The return spring  44  forces the adjusting screw  30  automatically back to its base position in the housing  11 . 
     FIG. 4 shows a cross-section through the leveling device  10  in the region of the support leg  17   a ,  17   b . There are total two support legs  17   a ,  17   b  on the opposite sides of the housing  11 . They are coupled with one another through a toothed gear transmission  55 . Each support leg  17   a ,  17   b  is non-rotatably connected with a toothed gear  56   a ,  56   b . Thus, by turning a first support leg  17   a ,  17   b  the corresponding another abutment leg  17   a ,  17   b  is also turned. 
     FIG. 5 shows the leveling device  10  with the unfolded support legs  17   a ,  17   b  which, because of the coupling through the toothed gear transmission  55 , are turned always uniformly. The abutment legs  17   a ,  17   b  extend outwardly through the support surface  13 , so that the leveling device  10  can be placed on any substrate, independently from the support surface  13 . This is usable especially in the event of uneven substrates. The adjusting screw  30  which is extended outwardly beyond the support surface  13  is recognizable between both support legs  17   a ,  17   b  with the support mandrel  33 . Because of the curved support edges  57   a ,  57   b  of the support legs  17   a ,  17   b , the leveling device  10  with the turned out abutment legs  17   a ,  17   b  is easily adjustable via the adjusting screw  30 . 
     It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the types described above. 
     While the invention has been illustrated and described as embodied in leveling device, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention. 
     Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention. 
     What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:

Technology Classification (CPC): 8