Abstract:
The invention concern a stand, in particular for a surgical microscope, in which provision can be made, by means of adjustment devices on the stand itself and not on the stand foot ( 2 ), for the pivot axis ( 30 ) of the carrier arm ( 11 ) to be plumb.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
         [0001]    This application claims priority of the German patent application 101 23 166.0 filed Mar. 30, 2001 which is incorporated by reference herein.  
         FIELD OF THE INVENTION  
         [0002]    The invention concerns a stand, in particular for a surgical microscope. The purpose of such stands is to hold a relatively heavy microscope so that it is movable by an operator with a minimum of resistance. An effort is therefore made to configure all joints, bearings, and the like in as low-resistance a fashion as possible, so that as little resistance as possible is presented to any arbitrary movement by the user.  
         BACKGROUND OF THE INVENTION  
         [0003]    The result of a greater smoothness of operation in stands is that, in event of irregularities in the installation location (uneven floor) but also in the event of changes in the loads on the stand, moments of force or torques can occur that cause portions of the stand, in particular the stand arm, to move in drifting fashion in the unbraked state. “Drift” is understood to mean lateral pivoting motions (about a rotation axis), or tendencies toward such pivoting motions of the carrier arm, that are undesired by the user.  
           [0004]    Three different actions for the reduction of drift are known from the existing art:  
           [0005]    1. Alignment of the stand foot. At least three of, for example, four support feet of the stand foot are made adjustable as to height, and a bubble level on the stand foot indicates its horizontal alignment. A device of this kind is implemented, for example, on the FM2 of the Mitaka company. It ensures a precise adjustment capability, but entails the following disadvantages: Because a three-point adjustment is involved, a displacement at one of the three points creates a need for readjustment at the other two adjustment points. Inexperienced persons have a great deal of difficulty making the adjustment in quick and effective fashion.  
           [0006]    There are further disadvantages as well:  
           [0007]    Firstly, the adjustment to the stand foot is made while stooped over near the floor.  
           [0008]    Secondly, a new adjustment must be made after each change of location, and possibly even after each load change on the stand arm, and usually on all three adjustment devices (or all the adjustment devices that are present).  
           [0009]    Thirdly, the installation of the adjustment devices forces the operating person to work, when making the adjustments, in the vicinity of the floor, i.e. in a region that is remote from the patient in an operating room and has a lower degree of sterility.  
           [0010]    In addition, an extra assistant might be needed in order to make the adjustments, whereas it would be desirable if an adjustment could be made by the surgeon or an operating room nurse him- or herself.  
           [0011]    2. The second known variant comprises a brake to increase the rotational friction. With such a brake, the advantage of smooth operation is deliberately abandoned in order to reduce drift. For the user, this disadvantageously results in an increased need for force when moving the carrier arm. For the surgeon, a high level of exertion makes it difficult subsequently to wield a scalpel, or to do other work that requires a steady hand.  
           [0012]    3. The third variant has hitherto been disclosed only in the context of ceiling mounts, and has nothing to do with the actual problem of changes in drift characteristics due to an uneven floor or the like, since in the case of a ceiling mount a fixed attachment point is usually provided from the outset, and no change takes place in the location on the ceiling. When the fixed installation point is created, it is of course optimally laid out so that a ceiling mount in principle has no drift. The adjustment in this context corresponds approximately to the leveling of a stand foot on the floor, although no further change in position is made after this adjustment. On the other hand, the loading of a ceiling mount, possibly with differing weights, creates another risk that in turn can generate drift:  
           [0013]    Because of the limited stiffness of a conventional horizontal stand arm that is attached to a vertical support, when a further stand arm attached to that horizontal carrier arm is bent about a vertical pivot axis, the weight of the further carrier arm and of the microscope attached to it results in a torsion on the first carrier arm. Conversely, a flexural load on the stand arm results when the stand arm is extended. The purpose and solution in the case of the ceiling mount was to attain a state in which the microscope lies at the same height when the stand arm is both in the bent position and in the extended position. Once this adjustment has been made, in principle it remains unchanged. A change in the position of one of the stand arms does not change the behavior. Changes in location on the ceiling do not occur.  
           [0014]    More detailed examinations of known stand assemblages, for example that of the Dräger series (the Dräger company in Germany has brought to market, under the product designation “Movita,” a series of ceiling mounts that are used in intensive medicine and intensive care) or that of the Kreuzer company in Germany, offer no way toward a solution, since with these ceiling mounts, pivoting movability for surgical microscopes with magnifying properties is not paramount.  
           [0015]    Greater frictional forces in rotary bearings do, however, keep them from running out of position, so that in known intensive-medicine ceiling mounts, the problem just mentioned does not even occur. What is required specifically in the case of microscope stands, however, is that the device not drift when the brakes are open, but can be moved with particular smoothness. There exist, for example, mouth switches with which the surgeon can, using his or her lips, on the one hand release the brakes and on the other hand reposition the brakes.  
           [0016]    In the aforementioned previously published Patent Application EP-A-1067419, FIGS.  5 - 7  and the relevant portions of the specification disclose a known mechanism of this kind for preventing drift in ceiling mounts. This known drift prevention device acts, if required, in only one plane. Since the one-time, completely leveled attachment point on the ceiling means that lateral irregularities do not occur, there was hitherto also no need to provide further leveling features or drift compensation features on a ceiling mount. In this respect, this teaching known per se also offers those skilled in the art absolutely no stimulus to ensure that an improvement is created in floor stands with regard to the problem mentioned initially, namely that changes in the inclination of the stand foot usually occur after a change in the location of floor stands.  
         SUMMARY OF THE INVENTION  
         [0017]    It is thus the object of the invention to discover an optimum adjustability for drift prevention on a stand, without impairing the smooth operation of the stand. In a further step, the intention is to discover a capability for performing drift compensation adjustment more quickly and easily than heretofore, and with no need for stooping.  
           [0018]    The basic idea in this context is to bring into plumb the axis about which the horizontal carrier arm would drift due to gravity if the assembly were not aligned.  
           [0019]    The object is achieved by application of the features of claim 1, in which at least one vertical rotation axis or at least one vertical rotary bearing of the stand can be brought, displaceably in at least two planes, into a perpendicular position with respect to the stand foot irrespective of the position of the upright column.  
           [0020]    A “stand foot” is to be understood as all those apparatuses which support a stand with respect to the floor. These may be conventional stand feet but also carriages, trolleys, or the like. “Upright columns” are to be understood not just as conventional vertical columns on a stand foot, but also as carrier arms or the like that are movable on rails, trolleys, or the like.  
           [0021]    Further embodiments and developments of the invention are recited in the dependent claims and in the description of the Figures. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0022]    The invention is explained in more detail, by way of example, with reference to sketches.  
         [0023]    [0023]FIG. 1 shows a simple stand assemblage with a stand foot and vertical column and pivoting arm;  
         [0024]    [0024]FIG. 2 symbolically shows an adjustable vertical rotary bearing;  
         [0025]    [0025]FIG. 3 shows an adjustable rotary bearing of this kind in a horizontal carrier arm (in section);  
         [0026]    [0026]FIG. 4 is a plan view of the assemblage shown in FIG. 3, partially in section;  
         [0027]    [0027]FIG. 4 a  shows a stand assemblage with spindles and X/Z and Y/Z carriages;  
         [0028]    [0028]FIG. 5 shows a variant of a pivotable rotary bearing on an upright column;  
         [0029]    [0029]FIG. 6 shows the variant according to FIG. 5 from a different perspective;  
         [0030]    [0030]FIG. 7 shows the variant from FIG. 5 in a plan view;  
         [0031]    [0031]FIG. 8 shows the assemblage according to FIG. 5 with some components removed;  
         [0032]    [0032]FIG. 9 shows the assemblage according to FIG. 5 in a different view, with an electric drive for drift adjustment;  
         [0033]    [0033]FIG. 10 shows the assemblage according to FIG. 9 in a different view, with the motor removed;  
         [0034]    [0034]FIG. 11 shows a variant of the assemblage according to FIG. 3 with automatically adjustable drift compensation;  
         [0035]    [0035]FIG. 12 shows an example of a stand according to the present invention in an overall view;  
         [0036]    [0036]FIG. 13 shows the assemblage according to the present invention as a schematic wire model; and  
         [0037]    [0037]FIG. 14 shows a detail of the wire model.  
     
    
       [0038]    The Figures are described in overlapping fashion; identical reference characters denote identical components; reference characters having the same numbers but different indices denote slightly different components having the same purpose or similar effects.  
       DETAILED DESCRIPTION OF THE INVENTION  
       [0039]    As is evident from FIG. 1, what are involved are fundamentally perpendicular axes  30   a, b  that can be arranged on the one hand directly on upright column  1   a , but on the other hand also on a carrier arm of stand  11   a  (as depicted e.g. in FIG. 3) or, as is evident from FIG. 2, about a rotary bearing  33   a  that receives or defines such a pivot axis  30   c . The purpose of the invention in the context of the adjustment of axes  30  or pivot bearing  33  is to bring the latter into plumb by way of manual or motor-controlled adjustment operations.  
         [0040]    [0040]FIG. 3 symbolically shows the construction of a displacement device in which, by means of a displacement screw  34   a , bearing tube  33   b  can be pushed against an elastic intermediate layer  66  because bearing tube  33   b  is held movably in a rotary pivot bearing  67 . Instead of a direct installation on an upright column, carrier arm  11   b  is supported on another carrier arm  11   a  that is held movably on an upright column or also, for example, in a wall rail mount. Since the problem of a change in drift behavior that is to be solved according to the invention occurs only when the physical placement point is changed with respect to the floor, in which context rotation axes can get out of plumb, ceiling mounts are excluded from consideration. On the other hand, for purposes of the invention a carrier arm  11   a  at least with its rotary pivot bearing  67  is to be understood as an upright column. On the other hand, a rotary pivot bearing  67  of this kind could also be incorporated directly into an upright column.  
         [0041]    It is evident from FIG. 4 that two or more displacement screws  34  can move bearing tube  33   b  within the elastic intermediate layer  66 .  
         [0042]    [0042]FIG. 4 a  symbolically shows the construction of a displacement apparatus that makes do with two spindles  38   a  and  38   b  that are arranged (e.g. in a vertical tube) each within an axially immovably mounted nut  37   a  and  37   b  respectively. Both a pushing motion (as in FIGS. 3 and 4 with displacement screw  34 ) and a pulling motion are thereby enabled. An X/Z carriage  39   a  and a Y/Z carriage  39   b  are provided to compensate for relative motions. When an adjustment is made on one side, these carriages  39   a, b  prevent the other side from also being influenced, since the carriage bearings tolerate a pivot motion of the Z axis that is stimulated from one side.  
         [0043]    [0043]FIG. 5 shows a variant embodiment of a rotary pivot bearing in which, with the aid of two displacement screws  34   c  and  34   d , a bearing sleeve  33   c  can be aligned in such a way that measurement sensor  61  (circular bubble level) indicates that bearing sleeve  33   c  is perpendicular. The measurement sensor is rigidly joined to bearing sleeve  33   c . The latter is pivotable about an axis  78  and about an axis  68 . The principle of this pivotability is depicted in FIGS. 13 and 14:  
         [0044]    A spherical bearing  79  forms the central articulation point for a shaft  72  that carries pivot bearing  33   c  in upright column  1 . Bearing  79  is held or configured on upright column  1 , and receives a ball  73   a  that is rigidly joined to shaft  72 . Simultaneously rigidly joined to said shaft is a yoke  74  that supports a pivoting yoke  75  at both ends. Pivoting yoke  75  is joined to a pivoting tongue  49 . A deflection of pivoting tongue  49  results in a pivoting of shaft  72  about its own axis  68  or about ball  73   a . As is evident from FIG. 14, in the embodied example bearing sleeve  33   c  is held by means of stub shafts  72   a  and  72   b , which replace shaft  72 . It is also evident from FIG. 14 that a pivoting of the pivoting tongue also pivots bearing sleeve  33   c.    
         [0045]    In order to make this bearing sleeve  33   c  also pivotable in a transverse direction, the end of shaft  72  is also held, for example by way of a ball  73   b , in a plain bearing  71  in which it can both pivot back and forth in the axial direction and rotate about its axis  68 . By means of threaded spindle  53 , plain bearing  71  is displaceable in its height position relative to upright column  1 . In this displacement, shaft  72  pivots in spherical bearing  79  without influencing pivoting yoke  75 .  
         [0046]    The pivoting motion about the two axes  68  and  78  is generated, in the preferred embodiment model as shown in FIG. 5, by turning displacement screws  34   c  and  34   d , which by way of conventional bevel gear drives or the like act on the one hand on pivoting tongue  49  and on the other hand on threaded spindle  53 .  
         [0047]    [0047]FIG. 6 shows the same variant embodiment from a different perspective, making visible a sliding member  48  that is laterally displaced by rotation of screw  34   d  and entrains pivoting tongue  49  that is mounted so as to slide up and down in sliding member  48 . Sliding member  48  is displaceable along a slide shaft  46  that is held in a holding block  45  secured to the upright column shaft.  
         [0048]    [0048]FIG. 7 shows a plan view thereof.  
         [0049]    In FIG. 8, the same variant embodiment is depicted with some components removed. It is evident in this depiction that displacement screw  34   c  drives a threaded spindle  53  by means of a bevel gear drive  44 . The vertical portion of bevel gear drive  44  drives spindle  53 , which modifies the height of slider  41  and thereby causes a deflection of bearing sleeve  33   c  about axis  78 . Spindle  53  is mounted in a guide block  40 , and could also be driven directly by a motor.  
         [0050]    Also visible is a portion of cover  51 , which forms the exterior of the upright column and can be attached to attachment pegs  76 .  
         [0051]    [0051]FIGS. 9 and 10 show the assemblage according to FIG. 5 with positioning motor  54  installed and removed. A comparable bevel gear drive  44   b  drives a spindle  53   b  which pivots slider  48  about its axis  68 . The motor has in its lower region a toothed-belt pinion over which a toothed belt can be looped in order to create the connection (not depicted in further detail) to the displacement linkage in bearing block  45 . Since the details of this assemblage are common knowledge to those skilled in the art, and any number of variants are conceivable, explanation in any further detail is superfluous.  
         [0052]    A simultaneous displacement of the two spindles  53  or shafts  50  thus results in a deflection of bearing sleeve  33   c  obliquely with respect to axes  78  and  68 . The pivoting about each of axes  78  and  68  may be made independently, and does not influence the other respective pivot position. In contrast to other similar level adjustment apparatuses, the displaceability is thus implemented in a manner comparable to a simple X-Y carriage but in pivoting fashion, which thus greatly simplifies operability even for inexperienced persons. This assemblage is further simplified by the replacement of the manually operated displacement screws  34   c  and  34   d  by electrical drives  54 , which are as indicated by way of example in FIG. 9 but can also be differently constructed and arranged.  
         [0053]    [0053]FIG. 11 once again shows the assemblage according to FIG. 3 in symbolic and simplified fashion, with no discussion of the pivot bearing; here the displacement of bearing tube  33  is accomplished automatically by means of drives  58  (merely indicated), by analysis of the data of angle sensor  61   a  or an electronic bubble level or electronic inclination sensor by computer  60 , and corresponding instructions to controller  59 .  
         [0054]    [0054]FIG. 12 shows an exemplary overall view of a stand according to the present invention with a stand foot  2   b , an upright column  1   c , and an equipment box  63  that because of its arrangement also serves to improve tipover resistance. The number  65  indicates a brake that, in the braked state, prevents the rotation of carrier arm  11   c  about vertical axis  30   c . Carrier arm  11   c  carries a further stand arm such as that indicated in German Patent Application DE 200 19 107. The details and technical embodiments recited therein in the Figures and associated Descriptions of the Figures are considered to be also disclosed herein.  
         [0055]    The Parts List which follows is a constituent of the Specification and supplements the Description of the Figures. The assemblages, apparatuses, and details recited in the Claims are also considered to be disclosed in the context of the Specification.  
         [0056]    The entirety of U.S. patent application Ser. No. ______ (claiming priority of German patent application 101 15 837.8 filed Mar. 30, 2001) filed on the same date as the present application and sharing the same applicant is incorporated herein by reference, since a possible further configuration of a stand according to the present invention is further described therein with other details. The teachings of the two patent applications can be combined with one another.  
                                         PARTS LIST                                1a, b, c   Upright column       2a, b   Stand foot       3   Nut       4   Surgical microscope       5   Auxiliary stand       6   Computer       7   Control system       8   Energy source       9   Carrier arm       10   Compensation arm       11a, b, c, d   Carrier arm part       12a, b   Distal carrier arm part       13   Ceiling bracket       14   Support columns       15   Support plate       16   Immovable building part, ceiling       17a, b, c   Damping layer       18a, b, c   Non-damping layer       19   Damping interface, damping element       20   Glass fiber cable       21   Equipment cabinet       22   Bridge       23   Vertical axis       24   Bracket       25   Display       26   Operating elements       27   Gas spring       28   Adjustment means       29   Pivoting part       30a, b, c   Support axis       31   Gimbal suspension       32   Bearing       33a, b, c   Bearing sleeve       34a, b, c, d   Displacement screw       35   Bridge       36   Damping peg       37a, b   Nut       38a, b   Spindle       39a, b   X/Z carriage       39b   Y/Z carriage       40   Guide block       41   Bearing block       42   Bearing       43   Guide rod       44   Bevel gear drive       45   Holding block       46   Slide shaft       47   Pivot axis       48   Sliding member       49   Pivoting tongue       50   Shaft       51   Cover shell       52   Shaft guide       53   Threaded spindle       54   Positioning motor       55   Entraining part       56   Arrow       57   Arrow       58   Motor       59   Controller       60   Computer       61   Measurement sensor       62   Linkage       63   Equipment box       64   Handle       65   Brake       66   Elastic intermediate layer       67   Rotary pivot bearing       68   Axis       69   Housing       70   Linkage       71   Plain bearing       72   Shaft       73a, b   Ball       74   Yoke       75   Pivoting yoke       76   Attachment peg       77   Toothed-belt pinion       78   Axis       79   Spherical bearing       III, IV   Section planes