Abstract:
An endoscopic instrument comprises a shaft, comprising a proximal end and a distal end. A grip comprising a handle is arranged at said proximal end of said shaft and a tool having at least an open and a closed position is arranged at said distal end of said shaft. Said shaft comprises at least two sections, a first section and a second section, which can be articulated with respect to said first section. Said second section comprises said tool. Said instrument further comprises an actuating element, by means of which said handle is in operative connection with said second section and with which an articulation of said second section can be initiated. Said first section or said actuating element and said tool are connected by a control element, by means of which said tool can be moved back and forth between said closed position and said open position in the course of an articulation of said second section, such that both the articulation of said second section and an opening/closing of said tool can be accomplished by the movement of said actuating element.

Description:
RELATED APPLICATION  
       [0001]     This application claims priority of German Patent Application No. 10 2004 052 204.9 filed on Oct. 19, 2004.  
       FIELD OF THE INVENTION  
       [0002]     The invention relates to an endoscopic instrument having a shaft, comprising a proximal end and a distal end, a grip comprising a handle being arranged at the proximal end of the shaft and a tool having at least an open position and a closed position, the tool being arranged at the distal end of the shaft, the shaft comprising at least two sections, a first section and a second section, which can be articulated with respect to the first section, the second section comprising the tool, the instrument further comprising an actuating element, by means of which the handle is in operative connection with the second section whereby an articulation of the second section can be initiated with said actuating element.  
         [0003]     An endoscopic instrument of this type is known for example from EP 0 582 295 B1.  
         [0004]     Such endoscopic instruments are used in minimally invasive surgery. This involves introducing surgical instruments into the body of a patient via small incisions under visual control through an endoscope, in order to perform manipulations there. The fact that, in minimally invasive surgery, the operating site no longer has to be completely exposed means that much smaller incisions are necessary, and consequently it is far less stressful for the patient. This reduces the time which a patient has to stay in hospital and sometimes even makes a stay in hospital superfluous. Furthermore, the possibility of pathogens getting into the patient&#39;s body is less. Consequently, with the aid of minimally invasive surgery it is possible nowadays for operations which previously necessitated a sometimes lengthy stay in hospital to be carried out on an outpatient basis.  
         [0005]     To make an insertion through a small incision possible, such endoscopic instruments generally have an elongated form, with a cross section that is as small as possible.  
         [0006]     However, it has been found that the possibilities for the use of such instruments are restricted, since an elongated instrument can only reach a restricted area around its distal end. Areas which are for example located at an angle of 90° from the instrument cannot be reached. It is also not possible with such an instrument to reach around an obstacle.  
         [0007]     Consequently, it is desirable for such an endoscopic instrument to have a section which can be articulated with respect to the endoscope. In this way it is possible for example to reach sites which lie behind an organ without this having the effect that the cross section of the endoscope is enlarged when it is inserted.  
         [0008]     Furthermore, the endoscopic instruments comprise tools at their distal end with which manipulations can be carried out in the patient&#39;s body. These instruments often have an open position and a closed position. The closed position may serve for example for minimizing the cross section of the instrument when it is inserted into the patient&#39;s body or serve the purpose of masking blades located on the tools when they are inserted into the patient&#39;s body, in order to avoid injuries.  
         [0009]     Such endoscopic instruments may be used for example as so-called retractors. They thereby serve the purpose of moving an organ, for example the liver, in the patient&#39;s body, so that the rear side of the organ can be investigated with the aid of an endoscope.  
         [0010]     In the case of such a retractor, both an articulation of a section of the shaft and the opening and closing of the tool are important. The articulation of a section of the shaft serves the purpose of placing the tool behind the organ, so that it can be moved.  
         [0011]     The opening and closing of the tool serves the purpose of forming a cross section that is as small as possible in the closed state during insertion, while in the open position it serves as a retractor, to offer the largest possible supporting surface for the organ, in order to distribute the force applied over an area that is as large as possible. As a result, injuries to the organ by the instrument are minimized.  
         [0012]     The interface between the first section and the second section may assume any form that creates a connection which can articulate in at least one direction. Examples of such connections are swivel pins, helical springs, hinges or combinations thereof.  
         [0013]     The grip and the handle may be configured in any form known from the prior art. The grip may be configured as a pistol grip, scissors grip, as a rod-shaped grip or in any form that allows manipulation of the instrument. The handle may for example take the shape of a scissors grip, a pulling or pushing element or a rotary knob, while the shape of the grip should be taken into consideration when designing the handle.  
         [0014]     Such endoscopic instruments are known for example from EP 0 582 295 B1. This document shows various endoscopic instruments which have an elongated shaft with a first section and a second section, which can be articulated with respect to the first section.  
         [0015]     Furthermore, tools with an open position and a closed position are arranged at the distal end of the shaft. These tools are arranged on the second section.  
         [0016]     Furthermore, there is an operative connection between the second section and an adjusting element arranged on the grip.  
         [0017]     In the cases shown in this document, however, it is not the second section that is connected to the handle, but the tool. The second section is connected to a second actuating element, that is to say the articulation of the articulating section and the opening and closing of the tool take place by means of two different drives.  
         [0018]     It follows from this arrangement that these endoscopic instruments cannot be used in a one-handed operation. However, this is often desirable, so that an operator has the second hand free, for example to adjust an endoscope for visual control.  
         [0019]     Furthermore, it has been found that it is often difficult to coordinate the articulation of the second section and the opening and closing of the tools with two hands.  
         [0020]     The instruments known from this document are also mechanically complex on account of the two drives that are present, the large number of components required being evident from the exploded drawings that are shown in this document.  
         [0021]     Such mechanical complexity makes these instruments cost-intensive to produce. Furthermore, disassembly, for example for cleaning purposes, is complicated and, because of the many individual parts engaging in one another, there are a large number of gaps and niches into which body fluids, bacteria or other contaminants can penetrate.  
         [0022]     It is therefore the object of the invention to provide an endoscopic instrument in which both the articulation of the second section and the opening and closing of the tool can be accomplished with a single drive. This would allow such an instrument to be used in one-handed operation.  
         [0023]     Furthermore, this would make a uniform, coordinated articulation of the second section and opening and closing of the tool possible.  
         [0024]     Furthermore, such an instrument should be as mechanically simple as possible.  
       SUMMARY OF THE INVENTION  
       [0025]     According to the invention the object is achieved by providing that, in the endoscopic instrument, the first section or the actuating element and the tool are connected by a control element having a first and a second end, by means of which control element the tool can be moved back and forth between the closed position and the open position in a course of an articulation of the second section, such that both a simultaneous articulation of the second section and a movement between the open position and the closed position of the tool can be accomplished by the movement of the actuating element.  
         [0026]     The measure stated above achieves the effect that the articulation of the second section and the opening and closing of the tool are coupled to each other. Consequently, both movements can be accomplished by a single drive. This provides an endoscopic instrument with an articulated section and a tool with at least one open position and one closed position which can be used in one-handed operation.  
         [0027]     The connection of the first section or the actuating element and the tool by means of a control element also ensures that the articulation of the second section and the opening and closing of the tool take place as a coordinated movement.  
         [0028]     The fact that the endoscopic instrument according to the invention now has only one drive means that it also has far fewer components than an endoscopic instrument according to the prior art. Consequently, an instrument according to the invention is less costly to produce and simpler to disassemble, for example for cleaning.  
         [0029]     Furthermore, since only one actuating element is required, the cross section of the shaft of the instrument, in which the actuating element runs, can be kept smaller.  
         [0030]     The control element can in this case be designed both as a single component and as a subassembly made up of components. If the control element is a single component, it may be for example a control rod or cable pull. Interengaging gear wheels or combinations of gear wheels and toothed racks may be used for example as the subassembly.  
         [0031]     In an embodiment of the invention, the control element is designed as a control rod.  
         [0032]     A control rod has the advantage that it produces a one-piece connection between the first section or the actuating element and the tool, which leads to a particularly fixed connection and an efficient force transmission between the two components. A control rod is also simple and inexpensive to produce.  
         [0033]     In a further embodiment of the invention, the first section and the second section are connected by means of a swivel axis.  
         [0034]     Although it is possible to connect the first section and the second section by means of any flexible component, such as a helical spring for example, a swivel axis is a preferred embodiment, since this provides a fixed connecting point between the two components. The articulation of the second section consequently takes place at a precisely defined point.  
         [0035]     The fact that a fixed connection between the first section and the second section is provided by a swivel axis also means that the force transmission from the actuating element to the second section is made more efficient, since such a connection has no further degrees of freedom in the direction of which the articulating section could deviate.  
         [0036]     In an embodiment of the invention, the tool is arranged movably about a pivot axis on the second section.  
         [0037]     In a way similar to the arrangement of the first section and the second section about a swivel axis, the arrangement of the tool about a pivot axis is a particularly fixed connection between the tool and the second section. As a result, the force transmission from the control element to the tool is also made particularly effective, since the tool once again has no further possibilities to deviate.  
         [0038]     In a further embodiment of the measures stated above, the first end of the control element is connected to the first section at a location which lies at a distance from the swivel axis.  
         [0039]     Such an eccentric connection of the control element to the first section allows for a circular movement of the second section, and consequently of the tool attached to it, in relation to the first section to be converted into a linear movement in a simple manner. During the articulation, the control element and the second section move on circular paths around two eccentric centre points. This causes changes in the distance between the two circular paths, described by the control element and the second section.  
         [0040]     Since the control element now has a fixed length, the distance of the first end, and consequently the distance of a second end, of the control element from a given point on the second section changes during the articulation. This linear relative movement between the control element and the second section can be used for moving the tool back and forth between an open position and a closed position.  
         [0041]     In a further embodiment of the measure stated above, a second end of the control element is connected to the tool at a location which lies at a distance from the pivot axis.  
         [0042]     An eccentric arrangement of the control element with respect to the swivel axis which connects the first section to the second section has the effect, as described above, of causing a linear relative movement between that point of the second section and the control element. Consequently, a linear relative movement is also caused between the pivot axis, by which the tool is arranged on the second section, and the control element.  
         [0043]     In the case of a connection of the actuating element to the first end of the control element, apart from its circular movement the control element performs a linear movement, since its fastening point is located on the linearly moving actuating element. Consequently, the centre point of the circular movement of the control element performs a linear relative movement in relation to the swivel axis, and consequently in relation to every point on the second section. The combination of the linear movement of the fastening point and the circular movement of the control element leads to a linear relative movement of the second end of the control element with respect to the second section and consequently also in relation to the pivot axis fixedly connected to the second section.  
         [0044]     If the second end of the control element is then connected to the tool at a location which lies at a distance from the pivot axis, a linear movement of the control element in relation to the second section leads to the connecting location between the control element and the tool moving in relation to the pivot axis. This linear movement is converted by this eccentric arrangement into a pivoting movement of the tool with respect to the second section. This allows the tool to be moved by the control element back and forth between an open position and a closed position in a simple way.  
         [0045]     In a further embodiment of the invention, the control element is connected by means of a ball joint at the first end to the first section or to the actuating element or at the second end to the tool.  
         [0046]     A ball socket as a mating component for a ball represents an articulated connection of two components which is simple to produce in production engineering terms but is reliable.  
         [0047]     Furthermore, the use of a ball socket produces only a few corners and undercuts, which are difficult to clean and in the long term could lead to accumulations of bacteria in the instrument.  
         [0048]     In a further embodiment of the invention, the control element is designed at least in a region of the second end as a toothed rack which is in operative connection with the tool by means of a gear mechanism.  
         [0049]     The combination of a toothed rack and a gear mechanism leads to a particularly secure connection, by the engagement of gear wheels in the toothed rack, and consequently to a very effective force transmission.  
         [0050]     In a further embodiment of the invention, the instrument is designed as a retractor.  
         [0051]     The combination of an articulated section and a tool which has an open position and a closed position has proven to be advantageous in particular for use in the case of retractors, since for example an organ can be gripped from the rear side and manipulated by the articulating section.  
         [0052]     The tool with an open position and a closed position has the advantage that a small cross section of the endoscopic instrument is created, for example by placing various retractor fingers one over the other during insertion in the closed position, so that it can be inserted easily through small incisions even into regions of the body of a patient that are accessible only with difficulty.  
         [0053]     In the open position in turn, the tool then offers a large supporting surface, so that the force exerted when an organ is being manipulated is distributed over a large area, whereby damage to the organ caused by overloading at single points is avoided.  
         [0054]     In a further embodiment, the retractor comprises at least two retractor fingers, it being possible for these to form a cross or a fan in an open position of the tool.  
         [0055]     The arrangement of at least two retractor fingers which form a cross in the open position has the advantage that, even with two retractor fingers, the force applied to the retractor can be distributed over a large surface area. Consequently, a large effective supporting surface can be created with only a few components.  
         [0056]     Configuring the retractor fingers in such a way that they form a cross in the open position also has the advantage that such a cross can be symmetrically designed, the point of application for an applied force being located approximately at the centre of the cross. This ensures that the force is distributed uniformly over the entire retractor fingers.  
         [0057]     Forming the retractor fingers in such a way that they form a fan in the open position has the advantage that a continuous supporting surface is thereby created in this way, so that possible injuries caused by tissue penetrating into intermediate spaces between the retractor fingers are minimized.  
         [0058]     It is understood that the above features and features described below can be used not only in the combinations specified but also in other combinations or in isolation without departing from the scope of the present invention. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0059]     The invention is described in more detail and explained below on the basis of selected exemplary embodiments in conjunction with the accompanying drawings, in which:  
         [0060]      FIG. 1  shows a perspective view of a first embodiment of an endoscopic retractor according to the invention, having the first section and the tool connected via a control element,  
         [0061]      FIG. 2  shows an enlarged perspective view of the distal section of the retractor from  FIG. 1  in the closed position,  
         [0062]      FIG. 3  shows an enlarged perspective view of the distal section of the retractor from  FIG. 1  in the open position,  
         [0063]      FIG. 4  shows an enlarged plan view of the distal section of the retractor from  FIG. 1  in the closed position,  
         [0064]      FIG. 5  shows a partial section through the distal section of the retractor from  FIG. 1  along the line V-V from  FIG. 2 ,  
         [0065]      FIG. 6  shows an enlarged frontal view of the distal section of the retractor from  FIG. 1  in the open position,  
         [0066]      FIG. 7  shows an enlarged exploded representation of the connection between the tool and the control element of the retractor from  FIG. 1 ,  
         [0067]      FIG. 8  shows an enlarged exploded representation of the connection between the distal section and the control element of the retractor from  FIG. 1 ,  
         [0068]      FIG. 9  shows an enlarged side view of the distal section of the retractor from  FIG. 1  in the closed position,  
         [0069]      FIG. 10  shows an enlarged side view of the distal section of the retractor in  FIG. 1  in the open position,  
         [0070]      FIG. 11  shows an enlarged side view of the distal section of a second embodiment of a retractor according to the invention in the closed position, the retractor hereby having the actuating element and the tool connected via a control element.  
         [0071]      FIG. 12  shows an enlarged side view of the distal section of the retractor from  FIG. 11  in the open position, and  
         [0072]      FIG. 13  shows an enlarged plan view of the distal section of the retractor from  FIG. 11  in the open position. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0073]     In the foregoing description of the drawings and in the following description, the expression “closed position” means that the second section is not articulated with respect to the first section, and the tool is in the closed position. The expression “open position” means that the second section is articulated with respect to the first section, and the tool is in an open position.  
         [0074]     In FIGS.  1  to  10 , an endoscopic instrument is denoted in its entirety by the reference numeral  10 . It is in this case an endoscopic retractor.  
         [0075]     This instrument  10  has a shaft  12  with a proximal end  14  and a distal end  16 . Arranged at the proximal end  14  of the shaft  12  is a grip  18 , which has a handle  20 .  
         [0076]     The grip  18  shown here is a scissors-like grip, the handle  20  likewise being designed as a scissors-like grip.  
         [0077]     Arranged at the distal end  16  of the shaft  12  is a tool, which is designed here as a pivoting cross  22 .  
         [0078]     The shaft  12  also has a first section  24  and a second section  26 , which can be articulated with respect to the first section  24 .  
         [0079]     Inside the shaft  12  there also runs an actuating element (not shown here), which connects the second section  26  to the handle  20 . If the handle is then displaced to the right in the direction of the double-headed arrow  28  into the position represented by broken lines, the actuating element in the shaft  12  is displaced in the distal direction.  
         [0080]     This displacement has the effect that the second section  26  is articulated downwards by 90° in the direction of the double-headed arrow  30  about a swivel axis  32 , which is located at the distal end of the first section  24 . In the process, the pivoting cross  22  is pivoted by 90° with respect to the second section  26  about a pivot axis  34 , which connects the pivoting cross  22  to the second section  26 .  
         [0081]     Moving the handle to the left in the direction of the double-headed arrow  28 , that is back into its starting position, moves the second section upwards in the direction of the double-headed arrow  30 , back into its starting position. The pivoting cross  22  is thereby likewise pivoted back into its starting position.  
         [0082]     In order to increase the flexibility of an operator, the shaft  12  can also be turned with respect to the grip  18  about its longitudinal axis in the direction of the arrow  36 . Such turning allows the position of the second section  26  when it is articulated to be changed in relation to the handle  18 , so that the second section when it is articulated for example is not articulated as it is here in the plane of the grip  18  but for example at right angles thereto.  
         [0083]     In  FIG. 2 , a perspective view of the distal section of the endoscopic instrument  10  from  FIG. 1  is shown. It can be seen here that the second section  26  of the shaft  12  is designed as a swivel arm  37 . This swivel arm  37  is in operative connection with the distal end of the actuating element  38 .  
         [0084]     Here, the distal end of the first section  24  of the shaft  12  takes the form of a fork  40 , into which the swivel arm  37  is fitted and held there by a pin which forms the swivel axis  32 .  
         [0085]     Furthermore, the fork  40  has the sleeve  42 , which serves the purpose of connecting the first section  24  of the shaft  12  to a control element.  
         [0086]     The pivoting cross  22  has at its distal end a rounded-off profile, which together with the distal end of the swivel arm  37  produces the profile of a hemisphere. This hemispherical profile facilitates the atraumatic insertion of the instrument  10  into the body of a patient.  
         [0087]     In  FIG. 3 , the distal section of the instrument  10  is shown in the open position. The actuating element  38  has in this case been displaced in the distal direction in relation to the shaft  12  by actuating the handle  20 , as indicated in  FIG. 1 .  
         [0088]     The actuating element  38  is connected to the swivel arm  37  at a location which lies outside the swivel axis  32 . This eccentric arrangement has the effect that the linear movement of the actuating element  38  is converted into a circular movement of the swivel arm  34  about the swivel axis  32 .  
         [0089]     In this representation, the pivoting cross  22  has been pivoted with respect to the swivel arm  37  by 90° about the pivot axis  34 . It can be seen here that the pivoting cross  22  has a rounded-off profile on its underside. This profile has the effect of avoiding injuries to the surrounding tissue during the pivoting movement.  
         [0090]      FIG. 4  shows a view of the distal section of the instrument  10 , the components located in the instrument  10  being schematically represented by broken lines.  
         [0091]     The swivel arm  37  lies inside the fork  40  and is pivotably connected to the latter by means of the pivot axis  32 . The swivel arm  37  is also pivotably connected to the actuating element  38 . In the swivel arm  37  there runs a control element, which is designed here as a control rod  44 . The control rod  44  is substantially symmetrical and has a rod-shaped body  46 , which tapers at respectively opposite ends into a neck  48 ,  50 , which is respectively connected to a head which is designed as balls  52 ,  54 .  
         [0092]     The ball  52  located at the proximal end of the rod  44  is fixed in place, but mounted such that it is spatially movable in the manner of a ball, in that the sleeve  42  on one side of the fork  40  and a second sleeve  56  on the opposite side of the fork  40  from the sleeve  42  are operatively connected. The ball  54  at the distal end of the control rod  44  lies in a third sleeve  58 . This third sleeve  58  is connected in a lower section pivotably, but operatively to the pivoting cross  22  and runs in an upper section in a kidney-shaped milled clearance  60 , which extends in an approximately semicircular manner around the pivot axis  34  in the swivel arm  37 .  
         [0093]     The third sleeve  58  and the milled clearance  60  can be seen even better in the sectional drawing shown in  FIG. 5 . Here it can be seen that the ball  54  of the control rod  44  comes to lie in a bore of the sleeve  58 , the neck  50  of the control rod  44  being led through a slit in the sleeve  58 .  
         [0094]     In  FIG. 6 , a frontal view of the instrument from  FIG. 1  is shown in the open position. In order to bring the instrument into this position, the handle  20  was displaced with respect to the grip  18  in the way represented in  FIG. 1 , whereby the actuating element  38  was displaced in the distal direction in relation to the shaft. The swivel arm  37  is now articulated by 90° with respect to the first section  24  of the shaft  12 .  
         [0095]     The swivel arm  37  thereby describes a circular path around the swivel axis  32  (not shown here), which lies in the same plane as the two sleeves  42 ,  56 , but in this representation is arranged offset into the plane of the paper.  
         [0096]     At the same time as the circular movement of the swivel arm  37 , the control rod  44  performs a circular movement about an axis which is defined by the sleeves  42 ,  56 , which produce the operative engagement between the ball  52 , and consequently the control rod  44 , and the first section  24 .  
         [0097]     If the pivot axis  34  is taken as a reference point for a circular movement of the swivel arm  37 , a first circular path is defined in this way. A second circular path is defined by the control rod  44  with the ball  54  describing a circular path whose centre point is formed by the ball  52 .  
         [0098]     Since the circular path of the pivot axis  34  has a different centre point than the circular path of the ball  54 , the distance between the ball  54  and the pivot axis  34  changes during the movement of the swivel arm  37 . The distance between the pivot axis  34  and the ball  54  becomes shorter until the ball  54  is offset to the rear, seen from distal to proximal in the direction of the instrument. The ball  54  and the sleeve  58 , in which the latter is held with non-positive engagement, thereby move in the milled clearance  60  of the swivel arm  37 . Since the sleeve  58  is operatively connected to the pivoting cross  22 , the pivoting cross is articulated with respect to the swivel arm  37  along the path predetermined by the milled clearance  60  and is pivoted by an angle of 90° with respect to the swivel arm  37 .  
         [0099]     In  FIG. 7 , the pivoting cross  22  is shown in more detail. The pivoting cross  22  has a central bore  62 , which serves for receiving the pivot axis. Offset with respect to the bore  62 , a further bore  64  is provided in the pivoting cross  22 . This bore  64  is a blind bore.  
         [0100]     Fitted in this blind bore is a sleeve  58 . Although it is possible to configure the bore  64  as a through-bore, a blind bore is to be preferred, since this makes it possible without a further holding device for the sleeve  58  to be fitted in such a way that it does not fall out of the pivoting cross.  
         [0101]     The distal section of the control rod  44  is fitted into the sleeve  58 , the distal neck  50  coming to lie in a slit  66  of the sleeve  58  and the ball  54  at the distal end of the control rod  44  coming to lie in the bore  68  of the sleeve  58 .  
         [0102]     This structural design has the effect that the control rod  44  is connected operatively to the pivoting cross  22 , but is still freely pivotable with respect to the centre point of the bore  64 .  
         [0103]     If the pivoting cross  22  is then held in the section of the first bore  62  and a pushing or pulling force is exerted on the control rod  44  connected operatively to the pivoting cross  22 , the sleeve  58 , and consequently the bore  64 , is moved on a circular path around the first bore  62 , and consequently the pivoting cross  22  pivots about the bore  62  or a pivot axis  34  possibly to be fitted into it.  
         [0104]     In  FIG. 8 , the fork  40  which forms the distal end of the shaft  12  is shown. This fork  40  has at the distal end two aligned bores  70 ,  72 . The sleeves  42 ,  56  can be inserted into these bores  70 ,  72 . The control rod  44  is then inserted with its proximal end into the fork  40 , so that the ball  52  is aligned with the bores  70 ,  72 . After that, the sleeves  42 ,  56  are inserted through the bores  70  and  72 , respectively. The sleeves  42 ,  56  thereby enclose the ball  52 , the sleeve  42  having a slit  74  and the sleeve  56  having a slit  76 , which can be brought into alignment with each other. The neck  48  of the control rod  44  comes to lie in a wide slit designed by the slits  74 ,  76 , and the ball  52  comes to lie in the bore  78  of the sleeve  42  and the bore  80  of the sleeve  56 . Consequently, the control rod  44  is connected to the fork  40  operatively, but pivotably about an axis which is formed by the centre axis of the bore  70  and  72 .  
         [0105]     The fork  40  also has the bores  82 ,  84 , which are in alignment with each other and are provided for receiving the swivel axis  34  for the swiveling of the swivel arm  37 .  
         [0106]     In  FIG. 9 , a side view of the distal section of the instrument  10  from  FIG. 1  is shown, the internal mechanical components being represented by broken lines. Here, the swivel arm  37  is connected to the fork  40  pivotably about the axis  32 . The swivel arm  37  is also movably connected to the actuating element  38  by a pin  86 .  
         [0107]     It is also clear from this representation that the swivel arm  37  has a further kidney-shaped milled clearance  88 , in which the sleeves  42 ,  56  and the ball  52  arranged at the proximal end of the control rod  44  are received.  
         [0108]     It can also be seen in this drawing that the sleeve  58  comes to lie partly in the bore  64  of the pivoting cross  22  and partly in the milled clearance  60  of the swivel arm  37 . The pivot axis  34  is designed here as a rivet.  
         [0109]     If the handle  20  of the instrument  10  is then actuated, the actuating element  38  is displaced in relation to the shaft  12  in the distal direction, that is in the direction of the arrow  90 . As a result, a pushing force is exerted in the same direction on the pin  86 , which connects the actuating element  38  to the swivel arm  37 .  
         [0110]     This pushing force has the effect that the pin  86  is displaced on a circular path around the pivot axis  32 , whereby the swivel arm  37  performs a swiveling movement in the direction of the arrow  92 . This swiveling movement has the effect that the pivot axis  34  moves on a circular path around the swivel axis  32 . Furthermore, the swivel arm  37  moves over the kidney-shaped milled clearance  88  around the sleeves  42 ,  56  and the ball  52  of the control rod  44 .  
         [0111]     The position of the ball  52  in relation to the fork  40  or in relation to the swivel axis  32  remains unchanged when this happens. Since the swivel axis  34  is in operative connection with the pivoting cross  22  and this pivoting cross  22  is in operative connection with the ball  54 , the ball  54  is led around the ball  52  on a circular path. Therefore, two eccentric circular movements are involved here.  
         [0112]     With such eccentric circular movements, the relative position of the circular paths with respect to each other changes, that is in this case the relative position of the ball  54  of the control rod  44  with respect to the pivot axis  34  of the swivel arm  37  changes. The ball  54  of the control rod  44  is hereby offset in relation to the pivot axis  34  of the swivel arm  37  in the direction of the arrow  94  towards the axis  32 .  
         [0113]     This relative movement of the ball  54  has the effect of exerting a pulling force via the sleeve  58  and the bore  64  on the pivoting cross  22 . This pulling force moves the ball  54  on a circular path around the pivot axis  34 , whereby the pivoting cross  22 , which is operatively connected to the ball  54 , performs a pivoting movement about the pivot axis  34  in the direction of the arrow  96 .  
         [0114]      FIG. 10  shows the same view as  FIG. 9 , but in the open position of the endoscopic instrument  10 . It can be seen here that the ball  54  is offset with respect to the pivot axis  34  in the milled clearance  60 . The pulling force thereby exerted on the sleeve  58 , and consequently the bore  64 , has pivoted the pivoting cross  22  with respect to the swivel arm  37  by 90° about the pivot axis  34 .  
         [0115]     It can also be seen that the milled clearance  88  has moved around the ball  52  and the sleeve  42 .  
         [0116]     In this open position, both the swivel arm is angled and the pivoting cross is articulated with respect to the swivel arm.  
         [0117]     In this position, the retractor can be used, for example in a minimally invasive operation, to grasp an organ, for example the liver, from behind and move it, in order for example to make an examination of the rear side of the liver possible.  
         [0118]     In  FIG. 11 , a side view of a distal section of a further embodiment of an endoscopic retractor is shown, the internal mechanical components being represented by broken lines.  
         [0119]     Here, the endoscopic retractor has a shaft  100 , which has a first section  102 , which is designed here as a fork  104 , and a second section  106 , which is designed here as a swivel arm  108 .  
         [0120]     The swivel arm  108  lies in the distal end of the fork  104  and is pivotably connected to the latter by means of a swivel axis  110 , which here takes the form of a pin.  
         [0121]     A tool of the endoscopic retractor that is arranged on the second section  106  of the shaft  100  here takes the shape of a fan, which has retractor fingers  112  and  114 . The retractor fingers  112 ,  114  are mounted pivotably in the swivel arm  108  by means of a swivel axis  116 , which is designed here as a screw. The distal end of the swivel arm  108  and the distal ends of the retractor fingers  112  and  114  are rounded off here and form an approximately hemispherical profile, which makes the atraumatic insertion of the instrument into the body to the greatest extent possible.  
         [0122]     At its proximal end, the swivel arm  108  is also connected by a pin  118  to an actuating element  120 . The actuating element  120  is connected at its proximal end to a handle in a way analogous to the instrument  10  from  FIG. 1  and can be moved axially by means of this handle.  
         [0123]     An axial movement of the actuating element  120  has the effect of causing an articulation of the swivel arm  108  with respect to the fork  104 . For this purpose, the pin  118  is located in an eccentric position with respect to the swivel axis  110 . If the actuating element  120  is then moved in an axial direction, the pin  118  performs a circular movement around the swivel axis  110 , whereby the swivel arm  108  is articulated with respect to the fork  104 .  
         [0124]     The actuating element  120  is also connected to a control element, which is designed here as a control rod  122 . The control rod  122  is substantially symmetrical and has a rod body  124 , which tapers respectively in the direction of its proximal and distal ends to a rod neck  126  and  128 , respectively.  
         [0125]     The rod necks  126 ,  128  are adjoined proximally and distally by heads of the control rod  122 , which are designed here as balls  130  and  132 , respectively.  
         [0126]     The ball  130 , located at the proximal end of the control rod  122 , lies in a slit sleeve  134 , which is connected fixedly, but pivotably, to the actuating element  120 , the proximal neck  126  of the control rod  122  coming to lie in a slit of the sleeve  134 .  
         [0127]     The ball  132  at the distal end of the control rod  122  comes to lie in a slit sleeve  136 . This slit sleeve  136  is displaceably arranged in a milled clearance  138  in the swivel arm  108 . The slit sleeve  136  is also displaceably arranged in with respect to the milled clearance  138  of the swivel arm  108  obliquely arranged milled clearances  140  and  142  in the retractor fingers  112  and  114 , respectively. The ball  132  at the distal end of the control rod  122  thereby comes to lie in the sleeve  136 , while the rod neck  128  at the distal end of the control rod  122  comes to lie in a slit of the sleeve  136 .  
         [0128]     If the actuating element  120  is then moved with the aid of the handle (not shown here) in the direction of the arrow  144  from proximal to distal in the direction of the shaft  100 , the pin  118  describes a circular path around the swivel axis  110  in the direction of the arrow  146 . This causes an articulation of the swivel arm  108  with respect to the fork  104 , likewise in the direction of the arrow  146 .  
         [0129]     The fact that the control rod  122  is fixedly connected to the actuating element  120  by means of the sleeve  134  and the ball  130  has the effect that the control rod  122  likewise performs a linear movement in the direction of the arrow  148  with respect to the swivel arm  108 . As a result, the sleeve  136 , fixedly connected to the control rod  122  by means of the ball  132 , is displaced in the milled clearance  138  in the distal direction that is likewise in the direction of the arrow  148 . The sleeve  136  thereby moves in the with respect to the milled clearance  180  obliquely arranged milled clearances  140  and  142  in the retractor fingers  112  and  114 , respectively. This movement has the effect that the retractor fingers  112 ,  114  are pivoted about the pivot axis  116  with respect to the swivel arm  108  in the direction of the double-headed arrow  150  in respectively opposite directions.  
         [0130]     In  FIG. 12 , the retractor from  FIG. 11  is shown in the open position. The actuating element  120  has been displaced for example with respect to the swivel axis  110  in the direction of the distal end of the shaft  100 . The pin  118  has thereby performed a circular movement around the swivel axis  110 , whereby the swivel arm  108  has been articulated at an angle of 90° with respect to the fork  104 .  
         [0131]     The sleeve  134 , and thereby the ball  130 , at the proximal end of the control rod  122  have likewise been displaced with respect to the swivel axis  110  in the distal direction. Furthermore, the ball  132  at the distal end of the control rod  122 , since it is fixedly connected to the swivel arm  108 , has performed a circular movement around the ball  130  at the proximal end of the control rod  122  and around the sleeve  134 .  
         [0132]     This combined linear and circular movement has the effect that the ball  132  at the distal end of the control rod  122  has been displaced in the distal direction with respect to the pivot axis  116 . As a result, the sleeve  136  has been displaced in the milled clearance  138  of the swivel arm  108 . During this linear movement of the sleeve  136  in the milled clearance  138 , the sleeve  136  slides through the oblique milled clearances  140  and  142  of the retractor fingers  112  and  114 , respectively, which respectively have bevels in different directions, whereby they were respectively pivoted in different directions about the pivot axis  116  with respect to the swivel arm  108 .  
         [0133]      FIG. 13  represents this open position once again in plan view. The swivel arm  108  has been articulated with respect to the fork  104  about the swivel axis  110  at an angle of approximately 90°. The retractor fingers  112  and  114  have respectively been pivoted in different directions with respect to the swivel arm  108  about the pivot axis  116 . As a result, the swivel arm  108  and the two retractor fingers  112  and  114  assume a fan-shaped configuration.  
         [0134]     This configuration has the effect that the supporting surface of the swivel arm  108  is significantly increased, and consequently a force exerted by the swivel arm  108 , for example on an organ, is distributed over a significantly larger area, whereby injuries to the organ caused by local overloading are avoided.