Abstract:
The microsurgical microscope system with a stand with three parallelogram linkages and a microscope arranged thereon is characterized in that a second parallelogram linkage and a third parallelogram linkage have a common bar inclined at an angle of approximately 30° to 60° to the vertical.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The invention relates to a microsurgical microscope system with a stand and with a microscope arranged thereon, in which the stand has: a base part, a first substantially vertical parallelogram linkage, of which one bar of the substantially vertical bars is mounted on the base part so as to pivot about a pivot axle, a second substantially horizontal parallelogram linkage with two substantially horizontal bars and two further bars, of which one substantially horizontal bar is a continuation of the upper substantially horizontal bar of the first parallelogram linkage, and a mounting device for the microscope being arranged on the first further bar arranged at a distance from the first parallelogram linkage, and a third substantially vertical parallelogram linkage whose first lower hinge on the pivot axle of one of the substantially vertical bars of the first parallelogram linkage is connected to the base part, and whose second lower hinge is likewise connected to the base part and is connected via its upper bar to the second parallelogram linkage.  
           [0002]    For operations on fine biological structures, in particular for neurosurgical operations on the brain and spinal cord, but also in the ENT field, operating microscopes are used which are arranged on easily movable stands near the operating site.  
           [0003]    Depending on the type of operation, operating microscopes and stands of different size and design are used. In neurosurgery, systems have proven particularly useful in which the stand has weights which, in the manner of a balance, compensate the weight of the operating microscope. However, since the microscope has to be moved in the three spatial directions, the stand must have at least three axes of movement. While one axis can be arranged vertically and for this reason no weight compensation has to take place around this axis, it is necessary to effect the balance about two axes by changing the weights or moving the weights.  
           [0004]    A great many examples of such stands can be found in the patent literature. In particular, U.S. Pat. No. 5,528,417 describes a system in which the microscope weight is compensated by a counterweight which is moved along a curve depending on the weight of the microscope. In this system, the holder for the microscope is additionally held horizontally by connecting bars, so that the microscope is always suspended vertically under the holder.  
           [0005]    In the aforementioned microscope system, the second and the third parallelogram linkages are connected via a lever to two branches which enclose an angle of  90 °. The lower branch is always held horizontally, and the upper branch is always held vertically. This admittedly results in quite a large pivot range for the second parallelogram linkage and, consequently, for the microscope arranged thereon. However, in the normal position when the second parallelogram forms a rectangle, the second parallelogram is horizontal, so that the operator may strike his head against it. For this reason, in the prior art it is necessary for the substantially horizontal bars to be arranged higher up or for them to be curved away from the operating site.  
           [0006]    The object of the invention is to create a microscope system which is very user-friendly while at the same time affording more space for the operating surgeon.  
         SUMMARY OF THE INVENTION  
         [0007]    The solution according to the invention lies in the fact that the second lower hinge of the third parallelogram linkage is arranged higher than the first, and in that the connection line between first and second hinges forms with the horizontal an angle of 30° to 60°, and in that the upper bar of the third parallelogram linkage forms the second further bar of the second parallelogram linkage.  
           [0008]    In this case, the bar of the second parallelogram linkage which is in proximity to the first and third parallelogram linkages is not vertical, but instead inclined at an angle of approximately 30° to 60°, preferably 45°, so that in this normal position the second parallelogram linkage is directed obliquely upwards and the operating surgeon has room below this.  
           [0009]    Depending on the operation, the operating microscope requires different additional parts which change the weight of the microscope. The system must therefore be balanced again after the microscope has been adapted.  
           [0010]    However, the regularly required weight compensation has disadvantages. Upon compensation of the shift in weight, the range of compensation is limited and, if appropriate, has to be extended by arranging additional weights on the stand. In the case of automatic balancing, a high level of electromechanical input is required, which considerably increases the costs of a system. If it is forgotten to carry out the balancing procedure, this results in inconvenience for the surgeon and even a risk to the patient as a result of uncontrolled movements of the microscope.  
           [0011]    For the reasons stated, the microscopes are equipped with all the necessary accessory parts, even when these are not needed for an operation. In this way, it is possible to avoid the balancing procedure which is carried out before the operation and the possible associated risk of imbalance. The disadvantage, however, is that the microscope system is rendered large and unwieldy by the many accessory parts and impedes the view of the operating field.  
           [0012]    The above disadvantages can be avoided if, according to the invention, provision is made that a receiving device for accessory parts of the microscope and/or additional weights is connected to the first further bar of the second parallelogram linkage.  
           [0013]    The invention makes use of the knowledge that because of the particular construction of this microscope system the balancing does not change if the weight acting on the second parallelogram linkage does not change. This weight does not change, however, if parts of the microscope, which is connected to the first further bar of the second parallelogram linkage, are removed and are arranged in or on the receiving device for the accessory parts, which is likewise connected to the first further bar of the second parallelogram linkage. The fact that the distance of these objects from the base part or any of the hinges of the parallelogram linkage changes, which change would cause different rotational moments, surprisingly plays no role here. This is due to the fact that, even upon swiveling of the parallelogram linkage, the orientation of the first further bar of the second parallelogram linkage and of the microscope and accessory parts arranged thereon does not change.  
           [0014]    Accessory parts which are not required at a given time do not therefore impede the work with the microscope because they can be removed from the microscope and can be arranged in or on the receiving device for accessory parts, where they no longer obstruct the work with the microscope. The corresponding parts do not have to be carried through the operating theatre and in particular taken to other rooms, which would entail the risk of these parts being damaged, mislaid or contaminated. A new balancing procedure after exchange of an accessory part is not necessary. Instead, the balancing procedure can be carried out once for a defined microscope and for a defined set of accessory parts. No automatic balancing devices of any kind are required any longer. In this way, the stand as a whole can be made lighter, smaller and less expensive.  
           [0015]    In some circumstances, the accessory parts for the microscope take up a relatively large amount of space, so that it can be difficult to accommodate them at the end of the second parallelogram linkage in the receiving device. In this case, a receiving device for accessory parts of the microscope and for additional weights can be provided on the base part. For each accessory part in this case, an equally heavy additional weight is provided which, if it is made of solid metal for example, obviously takes up a much smaller volume than the accessory part. If the relatively large-volume accessory part is not needed, it can be accommodated in the receiving device on the base part, where there is sufficient space. In its place, the substantially smaller additional weight is then arranged in the receiving device at the outer end of the second parallelogram linkage near the microscope.  
           [0016]    Electrically or pneumatically releasable brakes are expediently arranged on hinges and/or the pivot axle. These brakes are released only if the stand is to be adjusted, that is to say the microscope is to be moved to another position.  
           [0017]    After all the necessary accessory parts and the corresponding additional weights are arranged in the receiving device on the second parallelogram linkage or on the microscope, this microscope system can be equilibrated. This is expediently done by weights which can be arranged on the parallelogram linkages, in particular on the first parallelogram linkage. This balancing can be carried out once by a technician or by a theatre nurse for a given system, and it can be retained as long as the additional devices for the microscope are not replaced by others.  
           [0018]    A particularly expedient configuration is characterized in that the bars of the parallelogram linkages are pipes which are held in bushings which form parts of the hinges and/or of the pivot axle. The hinge axles and/or the pivot axle can be arranged in the bushings outside the longitudinal axis of the pipes. To create more space for the operating surgeon, at least one bar of the parallelogram linkage can be curved in the direction away from the operating site.  
           [0019]    The base part will expediently rest on the floor and can be provided in a manner known per se with lockable castors. However, it could also be arranged, for example, on the wall or on the ceiling of the operating theatre. The base part expediently has a foot part and a column which is pivotable about a vertical shaft and on which the further parts of the stand are then arranged.  
           [0020]    However, the main feature of the invention is that, when the stand is swiveled, the angle at which the microscope and the receiving device for the accessory parts are oriented does not change. If the total weight of the microscope and of the accessory parts which are arranged on the microscope or on/in the receiving device does not change, the balance is maintained. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWING  
       [0021]    The invention will be described below on the basis of advantageous embodiments and with reference to the attached drawings in which:  
         [0022]    [0022]FIG. 1 shows the microscope system according to the invention in a diagrammatic view from the side;  
         [0023]    [0023]FIG. 2 is a detail of the encircled portion of FIG. 1 in cross section;  
         [0024]    [0024]FIG. 3 is a detail of another embodiment corresponding to the encircled portion of FIG. 1;  
         [0025]    [0025]FIG. 4 is another embodiment of the microscope system according to the invention in a diagrammatic view from the side;  
         [0026]    [0026]FIG. 5 is a detail of another embodiment corresponding to the lower left hand side of the parallelogram linkage of FIGS. 1 and 4; and  
         [0027]    [0027]FIGS. 6 a  and  6   b  are details of the receiving device for accessory parts for the microscope.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0028]    Referring to FIG. 1, a column  3  which is pivotable about a vertical axis is arranged on a foot part  1  via a hinge  2 . A first parallelogram linkage is arranged on this column  3  so as to pivot about a horizontal pivot axle  4 . This first parallelogram linkage has vertical bars  5 ,  6  and substantially horizontal bars  7 ,  8  which are each connected by hinges  9 . Balancing weights  10  with which the stand can be equilibrated are arranged on the lower left hinge  9 . The hinge connection which connects bars  6  and  7  could be an axle which is fixed to bar  7  or weight  10 . To this axle bar  6  is rotatably fixed. Also the weight  10  can be fixed to bar  7 . Weight  10  could e.g. be fixed to bar  7  with a screw thread connection in order that it can be changed. Instead of providing such weights  10  at just one position, it is also possible for such weights to be provided at another position, for example weights  11  on the lower bar  7 , as is shown in FIG. 1. Weight  11  can, as indicated in FIG. 1, be merely suspended from bushing  21  by a wire or a bar. It also could be fixed by a screw connection to bushing  21  or bar  7 . Movable weights could also be arranged on the bar  6  or  7 .  
         [0029]    The upper bar  8  of the first parallelogram linkage  5  to  9  is continued to the right and here forms part of a second parallelogram linkage which, in addition to said bar  8 , has a substantially horizontal bar  12  and two further bars  13 ,  14 . The bars  8 ,  12 ,  13 ,  14  are likewise connected by hinges  9  to form a parallelogram linkage. The bar  13  here forms a part of a further parallelogram linkage which, in addition to the bar  13 , has a part of the bar  5  of the first parallelogram linkage, as far as the pivot axle  4 , a further substantially vertical bar  15  which is mounted at  16  on the base part  1 ,  2 ,  3 , and which forms the connection between pivot axle  4  and hinge  16 . The connection line between pivot axle  4  and hinge  16  is in this case at said angle of approximately 30° to 60°, here in particular 45° (as shown in FIG. 1), to the horizontal, by which means the corresponding orientation of the bar  13  is fixed.  
         [0030]    The mounting device  17  for the microscope is connected to the further bar  14  which, even upon swiveling of the parallelogram linkage, remains parallel to the bar  13  and thus does not change its orientation. A receiving device  18  for accessory parts of the microscope is also connected to this first further bar  14  of the second parallelogram linkage. This receiving device  18  can accommodate not only accessory parts (not shown in the figure) of the microscope, but also additional weights whose mass corresponds to the mass of accessory parts which, when not in use, can be accommodated in a receiving device  19  on the foot  1  of the microscope. The microscope itself is indicated at  20 .  
         [0031]    As shown in FIG. 2 which is an enlarged cross section view of the encircled portion of FIG. 1, bars  6  and  8  are hollow pipes which are held in bushings  21  which form part of the hinges  9 . These hinges comprise two bushings  21  and an axle  22  which connects the two bushings in a rotational manner.  
         [0032]    As can be seen in FIG. 3, the relative rotation of the two bushings can be blocked by a brake which contains a solenoid or pneumatic cylinder  23  which can press a plunger  24  against axle  22  which in this case is fixed to upper bushing  21  and can rotate within lower bushing  21 .  
         [0033]    As can also be seen in FIG. 3, the axle  22  can be arranged outside the longitudinal axis  25  of the bar or pipe  8 . This, of course, can be the case also for other hinge axles or pivot axles.  
         [0034]    In FIG. 5, details of another embodiment are shown in which weight  11  is integral with bar  7 , this integral unit connecting the lower hinge  9  of bar  5  with weight  10 .  
         [0035]    Details of the receiving device  18  are shown in FIGS. 6 a  and  6   b . The receiving device in this embodiment comprises a tray  27  which is affixed to bar  14  and on which accessory parts can be placed. These parts can be received also by holders which e.g. are fixed to bar  14  as shown in FIG. 6 b . the receiving device further comprises a cover  26  which is pivotably connected to hinge  9 .  
         [0036]    Receiving device  18  remains horizontally positioned. Pivot axles  4  and  16  are arranged under a fixed angle with respect to the horizontal, in the figure under 45. Because  5 ,  4 ,  16 ,  15 ,  9 ,  13 ,  9  is a parallelogram linkage, also part  13  will be arranged under 45 with respect to the horizontal. Because  13 ,  9 ,  12 ,  9 ,  14 ,  9 ,  8  is also a parallelogram linkage, part  14  will be always parallel to part  13  and thus also always oriented under 45 with respect to the horizontal. Therefore, device  18  is always horizontally aligned if as shown in FIG. 1 if it is aligned under 45 with respect to part  14 .  
         [0037]    The rotational moment (torque) which is exerted by the microscope  20 , the receiving device  18  and the weights of the bars  8 ,  12 ,  13 ,  14  and the other parts of the second horizontal parallelogram linkage can be perfectly compensated by the counterweight  10  if the bar  15  is held fixed. If rotation of the bar  5  about the pivot axle  4  is permitted, it is possible that the stand falls to an extreme position. If the centre of gravity of the whole system is above the axle  4 , the system stretches fully, and if it lies under the pivot axle  4 , the bar  5  moves until the angle a reaches 90°. By means of the further weight  11 , the stand can now be compensated so that the centre of gravity lies in the pivot axle  4  and thus the microscope weight is compensated in each position irrespective of the angles α and β.  
         [0038]    The weights  10  and  11  can be positioned at different places. Thus, the weight  10  can be secured at any point on the bar  6 . The weight  10  can also be secured on the bar  7  or on the continuation thereof, in which case the weight  10  must then be made bigger or smaller to compensate the moments. The weight  11  can also be moved on the bar  7  or can be arranged on the bar  5  under the pivot axle  4  or on a downward continuation of the bar  5 . In the latter case, a variation of the weight  11  is likewise necessary according to the distance from the pivot axle  4 . The weights  10 ,  11  can also be combined partially or completely in one weight. The weights or parts thereof can also be arranged inside the bars  5 ,  6  or  7 . In this way it is possible to keep the width of the stand as small as possible and to minimize the deflection of counterweights, by which means the theatre nurse&#39;s access to the operating site is optimized.  
         [0039]    On at least two hinges  9  of the stand, brakes are arranged which can be opened or closed by electrical actuation. One such brake  23 ,  24  is shown in FIG. 3. If the microscope  20  is to be spatially moved, all brakes are released by pressing a button on a hand-piece of the operating microscope, as a result of which the microscope can be brought with minimal effort into any position inside the range of movement of the microscope  20 . These brakes are preferably arranged in the hinge  9  in the compensating weight  10  and in the pivot axle  4 , so that the weight of the brakes either has no influence or contributes to the weight compensation. The transformer for current supply is also preferably arranged at the hinge  9  at the weight  10 .  
         [0040]    The weights  10  and  11  are chosen such that, at a maximum weight of the operating microscope, the stand is fully compensated. The weights  10  and  11  are then fixed.  
         [0041]    On the mounting device  17  for the microscope there is a receiving device  18 , on or in which the accessory parts of the microscope can be arranged. This receiving device can either be a box or a holder with annular recesses similar to the fastening possibilities on the operating microscope, or a combination of the two. If, for example, the physician changes from a cranial operation, in which the assistant stands at the side of the operating surgeon, to a spinal column operation in which the assistant sits opposite the operating surgeon on the other side of the operating table, the theatre nurse only needs to remove the co-observation tube from the operating microscope and place it in the receiving device  18  on the mounting device  17  for the microscope to prepare for the operation. Conversely, she will remove a second viewing piece from the receiving device and will arrange it on the operating microscope  20  opposite the operating surgeon. In this way, the stand remains completely weight-compensated, without weights having to be moved or operating buttons having to be actuated. There is also no longer any need for the theatre nurse to carry an expensive optical element through the operating theatre or to a storage location and thus run the risk of the optical element being damaged.  
         [0042]    If the overall configuration of the microscope has to  1  be changed from time to time, for example by attachment of a lighter video camera, the stand has to be re-compensated only in these cases. This compensation should preferably be carried out by a service engineer or a hospital technician. To do this, weight elements are preferably either removed from or fitted on the compensating weights  10  and  11 , or other weight elements are added or removed in the area of the mounting device  17  for the microscope or in the area of the receiving device  18 . For this purpose, a set of weights is supplied with the operation system. In addition, the brake control is configured in such a way that the brakes in the pivot axle  4  and in the hinge  16  can be opened separately. For a technician, it is then a very simple matter to reestablish a perfect weight compensation with the new microscope weight.  
         [0043]    For fine adjustment at the time of installation or after a subsequent change in the supporting weight, smaller weights can be arranged on the bars  5 ,  6  or  7 , which smaller weights are moved and then fixed. It is also possible to design the weight  10  or  11  or both of them so that they are slightly displaceable, in order thereby to carry out fine adjustments.  
         [0044]    The bars  5 ,  6 ,  7 ,  8 ,  12 ,  13 ,  14 ,  15  are preferably designed as pipes, with different cross-sectional shapes being possible. The pipes can be connected to one another by bushings  21  (FIG. 3) in which the hinges for the movement are located. In this case, it is advantageous if the hinge axes are located outside the pipes. If in fact the pipe  8  is arranged above the hinges, height is gained for the surgeon when he is operating underneath the bars of the second parallelogram linkage. To gain still further height, it is also possible to provide the bar  8  with an upwardly directed curvature in the area in which the surgeon can stand during the operation. Such an embodiment is shown in FIG. 4.  
         [0045]    As has already been described, the size of the receiving device  18  must be such as to be able to receive the accessory parts of the operating microscope  20 . If many parts are to be changed from one operation to the next, it is also possible to accommodate these parts elsewhere, for example in a compartment  19  at the foot  1  of the stand, and, in their place, to remove different weights from this compartment  19  and arrange them in the receiving device  18 . Since these weights can have a much smaller volume, the receiving device  18  can turn out considerably smaller.  
         [0046]    Where reference is made to bars of the parallelogram linkages, this means the parallelogram sides. One of these parallelogram sides between pivot axle  4  and hinge  16  is not of course such a bar or does not need to be such a bar. This is also the case for other so-called bars, in particular the bar  14 . Instead of providing a bar  14 , the bars  8  and  12  could be connected with hinges  9  directly to the receiving device  18 .