Abstract:
The invention relates to a stereomicroscope ( 1 ) with a main body ( 3 ) and wit an interface device ( 2 ) which is connected to the main body ( 3 ) and/or to an accessory ( 4 ), either permanently or in a manner that does not permit easy removal, and the interface device ( 2 ) permits the rotation of the accessory ( 4 ) relative to the main body ( 3 ) in the manner of a pivot bearing ( 5 ).

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims foreign priority under 35 U.S.C. § 119 of Swiss Application No. 1789/99 filed Sep. 28, 1999. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to generally to microscopes, and more particularly to a stereomicroscope with an interface or a connecting device to which accessories can be attached. 
     2. Description of the Related Art 
     An established microscope, the “M841,” developed by Leica Microsystems AG of Heerbrugg, Switzerland, assignee of the present application, has two independent optical paths, each with its own zoom and with a shared main objective. The two optical paths are positioned at right angles, such that an assistant can directly watch a surgeon at work in the operating field. Given the independence of the two optical paths, there are no losses in light, so that both the surgeon and the assistant can view an optimally illuminated operating field. The M841 is frequently used in eye surgery. Here the assistant&#39;s tube is positioned to the side of the main microscope body, and thus to the side of the patient&#39;s head, on a bridge that projects outwards to a certain degree. 
     Depending on whether the right or the left eye is operated on, the assistant&#39;s tube is required on the left or right side of the patient&#39;s head, while the surgeon always sits in front of the patient&#39;s head and positions his or her surgeon&#39;s tube roughly in line with the head. 
     Reversing the position of the assistant&#39;s tube from right to left normally occurs in this manner: 
     a) removal of the surgeon&#39;s tube; 
     b) removal of the assistant&#39;s bridge; 
     c) remounting of the assistant&#39;s bridge, but swiveled 180° around the optical axis of the main objective; and 
     d) remounting of the surgeon&#39;s tube. 
     This change takes some time and requires skill. It is frequently the case, therefore, that technical assistants attempt to perform the change more simply and more quickly. They skip stage a) and attempt to remove the entire structure at once and perform the remounting according to steps b) and c). This “quick change” requires special skill and does not correspond to the procedure indicated by the manufacturer. 
     The literature, to be sure, discloses mechanisms that permit rotation of a tube device around an optical axis, but there it is performed for a different purpose and with different means. For example, German patent DE 3333471C2—like the prior and similar DE 1217099 B—describes a design permitting simultaneous observation for a first and second observer, in which two stereomicroscopes are so positioned one relative to the other that both observers view the same operating field. Here the two primary axes are positioned inside each other by means of a beam splitting mirror and are directed at the operating field. This design permits the two microscopes to be rotated around the optical axis, without the need for justification; i.e., the operator can select his own preferred angular tube position relative to the patient and the assistant&#39;s tube will follow it accordingly. Thus, positions on diametric sides of the patient can also be occupied. 
     The assembly there includes the surgeon&#39;s tube with the first microscope, including the assembly with the beam-splitter, and a second, associated microscope for the assistant. The assembly with the beam splitter can be rotated around the main axis of the first microscope. 
     Problems with respect to the speed of any desired change in position do not arise with this structure; nor are there any significant mounting requirements, since the “structure” (or “substructure”) is basically secured in undetachable form to the first microscope and hangs below the microscope. On the other hand, this known assembly cannot be universally employed, since the two microscopes are permanently secured to each other. 
     Apart from the above, this known solution has a serious disadvantage: because there are two microscopes, the assembly is large and heavy. The design of the splitting mirror leads to a reduction in brightness, both for the surgeon and for the assistant, and this is a disadvantage. The heavy weight has a particularly negative effect if the microscope is mounted on a stand, as is usually the case in the operating room. Heavy weights result in heavy counterbalancing weights and in a high center of gravity for the microscope stand. A high center of gravity has a negative effect on the tipping behavior of the assembly and should be avoided whenever possible. 
     SUMMARY OF THE INVENTION 
     The invention is based on the task of solving the problem of repositioning and allowing the bridge and the assistant&#39;s tube to be converted in a simpler and faster manner. The present invention solves this problem for the first time in a satisfactory way. 
     In a special embodiment of the invention, the disadvantages of using two microscopes, one for the surgeon and one for the assistant, are avoided due to two independent optical paths provided in one microscope. 
     In accordance with the present invention, an interface device is provided for connecting an accessory part, such as a bridge for linking an assistant&#39;s viewing, to a main body of a microscope. The interface device is characterized by the fact that it is connected to the main body of the microscope and/or to the accessory part, by a locking screw that is by design difficult to remove. For example, the screw head can have a a special design, such that its manipulation requires a special tool, or a cover can be provided for the screw, or the screw can be made unusable, so that the interface device is lastingly secured to the main body of the microscope. Locking screws as understood in the invention are all structural elements which make possible the locking of two structural elements. Included among these, therefore, are elbow lever clamps and the like. 
     The interface device generally comprises upper and lower circular parts that can rotate relative to each other and that are attached to each other to form a pivot bearing. In its lower region, the lower part is designed as a mounting cone. The upper part is designed as a connection device for receiving a mounting cone and consequently includes locking projections and a locking screw which will preferably be hard to manipulate, or will have a cover, or will otherwise be difficult to access and operate. 
     Naturally the bridge, which is designed to receive the assistant&#39;s tube, is equipped with a connection for the operator&#39;s tube; here, as is known, it is possible to attach any desired modules to the connections on the bridge. 
     Screws as understood in the invention are all structural elements which make possible the locking of two structural elements. Included among these, therefore, are elbow lever clamps and the like. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING FIGURES 
     The figures will be described in overlapping and interrelated fashion. They do not restrict the invention, but serve merely as examples for assemblies protected by the claims. The list of reference numerals, together with the disclosure contents of the patent claims, is to be understood as an integral part of the descriptive introduction. The nature and mode of operation of the present invention will now be more fully described in the following detailed description of the preferred embodiment taken with the accompanying drawing figures, in which: 
     FIG. 1 is a perspective view showing a microscope with an attached bridge and an interface device according to an embodiment of the present invention; 
     FIG. 2 a  is a side elevational view showing the bridge with a securely attached interface device according to an embodiment of the present invention; 
     FIG. 2 b  is a top plan view of the embodiment shown in FIG. 2 a;    
     FIG. 2 c  is a perspective view of the embodiment shown in FIGS. 2 a  and  2   b;    
     FIG. 3 a  is a cross-sectional view of an interface device according to the present invention; 
     FIG. 3 b  is a top plan view of the interface device shown in FIG. 3 a;    
     FIG. 3 c  is a perspective view of the interface device shown in FIGS. 3 a  and  3   b;    
     FIG. 3 d  is a side elevational view of the interface device shown in FIGS. 3 a - 3   c ; and 
     FIG. 4 is a side elevational view showing a bridge with a securely attached two-part hinge-like interface device according to another embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Two exemplary embodiments are described in greater detail on the basis of the drawings. 
     Referring initially to FIG. 1., a conventional microscope, e.g., a surgical microscope  1 , comprises a main body  3  and a housing  6 , that in FIG. 1 bulges out on one side and contains, for example, lighting unit. At its upper end the main body  3  has a connection for an interface device  2  according to the invention. The connection corresponds to a conventional mounting cone. The new feature of this connection, however, rests in the fact that it is connected to the interface device  2  by means of a locking screw  16  that is hard to remove. This difficulty of removal can be achieved giving the screw head a special design, such that its manipulation requires a special tool; or by providing a cover for the screw, or simply by making the screw unusable, so that the interface device  2  is lastingly secured to the main body  3 . 
     Referring also now to FIGS. 2 a - 2   c  and  3   a - 3   d , the interface device  2  generally comprises two circular parts  18   a  and  18   b  that can rotate relative to each other and that are attached to each other in the manner of a pivot bearing  5 . In its lower region, the lower part  18   a  is designed as a mounting cone  11 . The inner part  18   b , for its part, is designed as a connection device for a mounting cone and consequently includes locking projections  15  and a locking screw  14 , which, like the screw  16 , will preferably be hard to manipulate, or will have a cover, or will otherwise be difficult to access and operate. 
     In actual practice, the outer part  18   a  and the inner ring  18   b  could have reversed positions, such that the outer ring  18   a  is connected to an accessory above, while the inner ring is below. 
     The outer part  18   a  exhibits a release area  17 , in which the locking screw  14  is provided with play in the rotating direction of the two parts  18   a  and  18   b . The degree of play is precisely such as to permit rotation by the accessory part. In the depicted case, the degree of play is about 180°. 
     For reasons of mounting, the outer part  18   a  has two parts. The two parts are connected with screws  19 , but could also be riveted together or glued, or they could have a single-piece design. The turning motion between the outer parts  18   a  and  18   b  can be braked or stopped by a locking screw  10 . In the present embodiment, a snap mechanism is provided as the preferred form of locking. A locking ball  12 , which is powered by a catch spring  13 , locks with diametrically opposite snap-in holes  20  in the positions, or rotational positions, preferred for the two parts  18   a  and  18   b . As in the initially described case involving a surgical microscope for ophthalmology, these positions face each other over a 180° rotational angle. As seen in FIG. 2 b , stereo light paths  21  of a first stereo optical path for surgeon viewing pass upward through the bridge without hindrance. Meanwhile, stereo light paths  22  of a second stereo optical path for assistant viewing are angularly displaced by 90° relative to stereo light paths  21  of the first stereo optical path, and correspond in location to deflection mirrors for reflection of light into the assistant&#39;s tube through bridge  4 . 
     FIGS. 2 a - 2   c  depict a preferred embodiment of the invention, in which the interface device  2  is connected in fixed fashion to a bridge  4  serving as accessory, from which it can be disconnected only with difficulty. 
     The bridge  4  itself is known to the prior art and exhibits a locking screw  7  and a connection  8  for mounting an eyepiece tube, or the like. It also has a connection  9  for an assistant&#39;s tube, which is depicted in only schematic fashion and can also exhibit a mounting-cone device. 
     An important component of the invention, therefore, is the two-part interface device  2 , which permits rotation of the two parts, one relative to the other. In their mounted state, the two parts are inseparably connected in the manner of a pivot bearing; one part can be connected to the main body of the microscope  3 , and the other part can be connected to an accessory, e.g., an eyepiece tube. 
     Variations of the invention can be such that the entire interface device  2  is inseparably connected to the main body  3 ; or, as an alternative, the entire interface device  2  can be connected in non-detachable form to the accessory  4 . In the later two variations, the free and unattached connection area of the interface device  2  will exhibit a conventional connection, e.g., a mounting-cone, as well as a locking screw. 
     In the special assembly according to FIG. 4, interface devices  2 ,  2 ′ are provided on the upper and lower sides of the bridge, such that when the bridge  4  is rotated the original position of the microscope  3  and any tubes or the like mounted on the interface  2 ′ retain their relative position, without any parts having to be separable or removable in design. 
     According to another embodiment variant, parts  2  and  2 ′ can be rigidly connected, so that they form a kind of pivot, as in a hinge. The parts  2  and  2 ′ can be installed to enclose bridge  4  like a clamp. 
     The combination of the depicted features among themselves is also included within the scope of the invention, as are combinations of the indicated interfaces with any known microscope parts or accessory parts which heretofore were attached to comparable interfaces when the need arose. 
     List of Reference Numerals 
       1  stereomicroscope 
       2  interface device 
       2 ′ second interface device, when necessary attached along with the first interface device to a hinge-like component, on which the bridge  4  is mounted and locked in swivel fashion 
       3  main body 
       4  bridge, accessory part 
       5  pivot bearing 
       6  housing 
       7  locking screw for eyepiece tube 
       8  connection for eyepiece tube 
       9  connection for assistant&#39;s tube; in principle, it may be designed like connection  8   
       10  locking screw for rotation around the main objective axis 
       11  mounting cone 
       12  locking ball 
       13  catch spring 
       14  locking screw for attachment to accessory ( 4 ), also operates as a stop pin for rotating motion 
       15  locking projection 
       16  locking screw for attachment to main body ( 3 ) 
       17  release area 
       18   a,b  parts that can rotate in relation to each other 
       19  screw 
       20  snap-in holes 
       21  stereo light paths 
       22  stereo light path displaced 90°; located at this point, in undisplaced condition, are the deflection mirrors for reflection into the assistant&#39;s tube through bridge  4