Abstract:
The invention concerns a stand, in particular a microscope stand, having a multiple-part stand foot. The stand foot includes a removable stand foot body having cavities configured for enclosing and precisely positioning weights such that the weights can be installed without turning the stand foot over. A method for assembling such a stand is also described.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     Applicant claims foreign priority under 35 U.S.C. § 119 of Swiss Patent Application No. 0266/99 filed Feb. 7, 1999. 
     BACKGROUND OF THE INVENTION 
     A. Field of the Invention 
     The invention concerns a microscope stand used, for example, in connection with surgical microscopes, and a method for assembling a stand foot. 
     B. Description of the Prior Art 
     One of these stands with the designation “S 5 ” 0  offered by Zeiss has a hollow stand foot body into which weights can be inserted from the underside and can be secured or immobilized in the cavity of the stand foot body by way of transverse metal strips and bolts. The weights serve to improve the tipover resistance of the stand. 
     The disadvantage of this known construction is the great weight that results after installation of the weights. Because the weights must be installed from the underside, the stand foot must be placed on its upper side during assembly. After installation of the weights the stand foot, now heavier, must be turned over again. This is possible only with great exertion or with the assistance of several persons. The effect that is thus achieved by the division into multiple weights is partially canceled out again by this type of installation. Permissible working standards for one person are also thereby exceeded. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the invention to create an improved system and assembly method in which the total weight of the stand foot is never lifted up in the course of assembly, and in which the stand foot never needs to be turned over in the assembled state. 
     This object is achieved by a stand generally comprising a column and a stand foot for placement on a floor in a room, wherein the stand has at least one stand foot body that is or can be fitted with at least one weight. The stand also has a securing apparatus for securing the weight, wherein the securing apparatus can be actuated from the side of the stand foot that faces toward the room in the utilization position. 
     The fact that the securing apparatus is now usable from a side other than the underside of the stand foot eliminates the turning-over operation described above. This is advantageous not only during initial assembly, but also for each further assembly action, e.g. for transport purposes, service purposes, and demonstrations or the like. 
     The stand foot body includes a hollow body having at least one cavity, and the securing apparatus includes an assembly retainer and an immobilization apparatus that makes the cavity of the stand foot body closable on its side facing the floor in the utilization position. The immobilization apparatus is actuable from the side of the stand foot body that faces toward the room in the operating state. The weight can be roughly positioned on the assembly retainer, and at least two walls enclosing the associated cavity are configured such that they precisely position the weight during the immobilization operation. The immobilization apparatus preferably comprises at least one nut bolt coupling that passes through the stand foot body and makes the latter threadably joinable to the assembly retainer. 
     The stand foot body is configured with rotational symmetry about the vertical axis of the column, and has at its center a corresponding recess for the column. The recess includes a wedge that uses the column&#39;s own weight to press the column against the recess wall, and a bolt is preferably provided to extend radially through the wall of the recess to engage and clamp the column in place against the recess wall. 
     The invention also encompasses a method for assembling a stand. The method includes providing an assembly retainer, roughly positioning at least one weight on the assembly retainer, providing a threaded rod extending approximately from the center of the assembly retainer, slipping a hollow stand foot body over the assembly retainer and onto the weight or weights so that the threaded rod passes through a hole in the stand foot body and each weight resides within a cavity defined by the stand foot body, and tightening a nut on the threaded rod such that two or more cavity walls simultaneously precisely position each weight. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Details of the present invention are evident from the drawings, which depict an exemplary embodiment according to the present invention. The figures are described in overlapping fashion; identical reference characters denote identical components. Functionally identical components having possibly different conformations bear identical reference numbers with different letter indices. The figures do not limit the invention, but merely indicate exemplary embodiments of the invention. The nature and mode of operation of the present invention will now be more fully described in the following detailed description of the preferred embodiments taken with the accompanying drawing figures, in which: 
     FIG. 1 shows an exploded view of a stand according to the present invention in a schematic depiction, prior to assembly; 
     FIG. 2 shows a variant of the configuration of FIG. 1; 
     FIG. 3 shows a further variant of the configuration of FIG. 1 in plan view; 
     FIG. 4 shows the configuration of FIG. 3 in an oblique view; 
     FIG. 5 shows an embodied variant of the configuration of FIG. 1 in a lateral section through the stand foot body; 
     FIG. 6 shows a plan view of the configuration according to FIG. 5; 
     FIG. 7 shows a detail of a variant of the configuration of FIG. 5; 
     FIG. 8 shows a detail variant of FIG. 5; and 
     FIG. 9 shows a section through the wall of a stand foot body according to FIG. 8 between adjacent star-shaped arms. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     One of the preferred embodiments of the invention is evident from FIG.  1 . On an assembly retainer  10   a  that lies on the floor in the utilization position, four individual weights  9   a-d  are roughly by way of lugs  11   a-d  and counterpart lug recesses (see recesses  21   a-h  in FIG. 5) in weights  9   a-d . Precise positioning and immobilization of weights  9   a-d  is accomplished by setting in place a stand foot body  2   a  that has corresponding cavities for receiving weights  9   a-d . Stand foot body  2   a  has, in the center, a recess  4   a  terminating at a base  5   a , which can be a plate or configured in one piece with the stand foot body. A hole  6   a  passes through base  5   a  and fits onto a threaded rod  12   a  that is immovably joined —e.g. thread-joined, pressed, or welded—to assembly retainer  10   a . For immobilization, a nut  7  is threaded onto this threaded rod  12   a  until assembly retainer  10   a  is braced by way of weights  9   a-d  against stand foot body  2   a . Precise positioning of weights  9   a-d  is thus accomplished by the walls that delimit the cavity or cavities of stand foot body  2   a . In particular, it is conically configured walls that bring about this precise positioning. 
     The weights  9   a-d  are preferably be made of primed and/or painted gray cast iron, steel, brass, or other heavy metal. The stand foot body  2   a  is preferably manufactured from aluminum, in particular die-cast aluminum. 
     Stand foot  1   a  serves also to receive a column  3   a  that can be anchored in recess  4   a . Stand foot  1   a  carries not only transport casters  14  (not shown in FIG.  1 ), but also two brakes, of which brake pedals  13   a,b  are indicated in FIG.  1 . 
     The variant  1   b  according to FIG. 2 also has a stand foot body  2   b  that is constructed from four arm-like stand foot body parts. Each part has a cavity for reception of a weight. Each part is thread-joined from the top together with the weight enclosed in the cavity, by way of threaded rods  12   b-e , to an assembly retainer  10   b  in a manner identical or similar to the configuration according to FIG.  1 . 
     As a variant thereof, the bolts could also pass through weights  9   e-h  laterally, and in the assembled position could lie approximately horizontal with respect to floor  28 . This still allows access from the room, but on the other hand reduces the area subject to dirt penetration on the upper side of the weights. 
     Here as well, the effect desired in accordance with the present invention is thus achieved, and assembly can occur from above. The configuration of stand foot body  2   b  could, of course, also be one-piece. The purpose of the depiction of FIG. 2 is to indicate that according to the present invention, multiple bolts can also be used to join the stand foot body to the assembly retainer. 
     It should also be mentioned that variants in which a bolt can be threaded from top to bottom into the assembly retainer through the stand foot body, and optionally through the respective weight, are also within the context of the invention. Other types of immobilization, for example clamps or the like slid on laterally, are also encompassed, but the variants depicted are preferred. 
     FIG. 2 also serves to indicate the possibility provided according to the present invention of joining transport casters  14   a-d  to assembly retainer  10   b  so that in contrast to FIG. 5, for example, casters  14   a-d  are not joined directly to stand foot body  2   b . 
     FIG. 3 shows a further variant lc in which the weights are not received by way of a cavity but rather are bolted laterally onto stand foot body  2   c . This variant is not preferred for reasons associated with sterilization of the surgical microscope stand, since gaps remain between weights  9   e-h . For less critical areas, however, this simple configuration is advantageously usable. With this configuration it is also conceivable to do without an assembly retainer, by bolting weights  9   e-h  directly onto stand foot body  2   c . With this configuration, threaded rods  12   b-e  (indicated only symbolically) or bolts can also be threaded obliquely into stand foot body  2   c  or can project obliquely out of it. FIG. 4 shows the configuration of FIG. 3 in an oblique view. 
     The configuration of the stand foot  1   d  as shown in FIGS. 5 and 6 is a preferred embodiment. In addition to what has already been described, a particular shaping of the weights  9   i-l  with lug recesses  21   a-h  is evident. The lug recesses can of course be shaped differently in order, if applicable, to provide a greater degree of freedom for precise positioning. Located opposite lug recesses  21   a-b  are lugs  11   e-l , which are rivet-like in appearance and preferably are made from plastic. They are anchored in holes of assembly retainer  10   d . The advantage of such plastic lugs lies in the lower risk of abrasion on the weights that, for example, are not made from corrosion-proof material. Although according to a particular embodiment such weights are preferably primed or painted, abrasion which might expose the corroding material is nevertheless possible, specifically at lug engagement points. This is effectively prevented by the plastic. A side from this, the lugs and lug recesses can also be configured so that in the assembled state, the underside of weights  9   i-l  is spaced away from the upper side of assembly retainer  10   d , so that weights  9   i-l  rest on lugs  11   e-l . As an alternative to this, foam strips could also be introduced between the underside of the weights and the upper side of the assembly retainer, so that the weights are protected on all sides from mechanical abrasion and are also vibration-damped. Transport casters  14   b,c  are conventional casters mounted to stand foot body by bolts  16  extending through caster base  15 . 
     Recess  4   d  has, in the region of its support wall  19   a , at least one threaded hole  20   a,b  that, with a bolt (not shown), serves to immobilize column  3   a  (not shown in FIGS.  5  and  6 ). 
     As a special feature, the configuration shown in FIGS. 5 and 6 has a threaded-in threaded rod  12   f  that has on its end facing toward assembly retainer  10   d  a hex nut  7  with which it can be threaded into assembly retainer  10   d . Threaded or press fit mounting are indicated for portion  17  in FIG.  5 . For safety, this region can be covered with cover plate  23 . 
     FIG. 6 shows, by way of example, foam strips  22   a-m  that are applied onto the walls of stand foot body  2   d  delimiting the respective cavities, and in the assembled state ensure that weights  9   i-l  fit in wobble-free and damped fashion in the cavities. Thus, they also provide clearance compensation. 
     Also indicated is an oblique surface or wedge  27  that is preferably used, and a symbolically indicated bolt  24 , which are described in more detail in connection with the variant of FIG.  7 . 
     The particular detail in FIG. 7 shows a portion of a stand foot body  2   e  that has a wedge  26  in its recess  4   e  in the region of recess base  5   c . This wedge  26 , by way of its oblique surface  27 , exerts a lateral sliding force on the inserted column  3   b , so that the latter is positively pressed by the sliding force against wall  25  of recess  4   e  located opposite the wedge. As shown, column  3   b  preferably includes a corresponding oblique surface contacting surface  27 . Since this wall is perpendicular to the floor in the operating position, the column is thus also oriented vertically, regardless of diameter tolerances. A quasi-centering effect is thereby achieved. The center of the column can be displaced slightly out of the center of the stand foot (within the tolerance range of recess  4   e  and column  3   b ). The stand can also have a bevel in the region of  27 , but this is not mandatory. The advantage of this configuration, which can also be used independently of the other stand foot configurations according to the present invention, is that the stand can be attached easily with only one clamping bolt  24 , but nevertheless is securely “centered”. 
     According to a particular embodiment of the invention, recess  4  in stand foot body  2  is protected from wear. This can be brought about, for example, by way of a steel bushing in the recess of an aluminum stand foot body. 
     For assembly purposes, plate  5   b  shown in FIG. 5 can also be attached to stand foot body  2   d  by way of bolts (not shown). A variant of this is depicted in FIG.  8 . Plate  5   b  is in this case placed not from below but from above onto a radial projection of the wall of the stand foot body. Bolt  12   f  is held at its lower end with a nut on assembly retainer  10   d . In this example, lugs  11   i  are mushroom-shaped and made of plastic. 
     In all the figures, the assembly retainer is depicted as a baseplate. The invention also, however, encompasses variants in which a baseplate is absent and the weights can be attached to an assembly retainer that is shackle-shaped in section, and thus in the assembled state do not rest on the assembly retainer but rather hang from it. In alternatives thereto, neither the baseplate nor a shackle-shaped assembly retainer is present. With these alternatives, support extensions are provided on the stand foot body or the like for the weight or weights, the weight or weights being thread-joined to the stand foot body. Such support extensions may be imagined, for example, in FIG. 4 instead of baseplate  10   c . They would be joined, for example, to stand foot body  2   c  at its lower edge, and thus would support weights  9   e-h  just as in the exemplary embodiment illustrated. 
     It is preferred that the assembly retainer  10 , stand foot body  2 , and each weight  9  have a maximum weight defined in the context of permissible working standards for handling by one person. Typically, this is in the range of about 10-25 kg each. 
     List of Reference Characters: 
     
       
         
               
               
               
             
           
               
                   
               
             
             
               
                 1 
                 Stand foot 
                 a, b, c, d, e 
               
               
                 2 
                 Stand foot body 
                 a, b, c, d, e 
               
               
                 3 
                 Column 
                 a, b 
               
               
                 4 
                 Recess 
                 a, b, c, d, e 
               
               
                 5 
                 Base of recess 
                 a, b, c 
               
               
                 6 
                 Hole 
                 a, b, c 
               
               
                 7 
                 Nut 
               
               
                 8 
                 Column axis 
               
               
                 9 
                 Weight(s) 
                 a-d, e-h, i-l 
               
               
                 10 
                 Assembly retainer 
                 a, b, c, d 
               
               
                 11 
                 Lugs 
                 a-d, e-l 
               
               
                 12 
                 Threaded rod 
                 a, b-e, f 
               
               
                 13 
                 Brake pedal 
                 a-b, c 
               
               
                 14 
                 Transport casters 
                 a-d 
               
               
                 15 
                 Caster base 
               
               
                 16 
                 Bolt 
               
               
                 17 
                 Press fit or threaded fit 
               
               
                 19 
                 Support wall 
                 a, b 
               
               
                 20 
                 Threaded hole 
                 a, b, c 
               
               
                 21 
                 Lug recess 
                 a-h 
               
               
                 22 
                 Foam strip 
                 a-m 
               
               
                 23 
                 Cover plate 
               
               
                 24 
                 Clamping screw 
               
               
                 25 
                 Wall 
               
               
                 26 
                 Wedge 
               
               
                 27 
                 Oblique surface 
               
               
                 28 
                 Floor