Abstract:
An actuator for a surgical instrument. The actuator including: a sliding tube; and a rotor arranged in said sliding tube; wherein the sliding tube has at one end a receiving cavity for a rotor positioning key, the receiving cavity being configured such that after the rotor positioning key has been positioned in the receiving cavity, and after the rotor positioning key has been twisted in the receiving cavity, the rotor positioning key is releasably locked.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    The present application is a continuation of PCT/EP2013/003006 filed on Oct. 7, 2013, which is based upon and claims the benefit of DE 10 2012 219 354.5 filed on Oct. 23, 2012, the entire contents of each of which are incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    1. Field 
         [0003]    The present application relates to an actuator, particularly a bistable actuator, for a surgical instrument, particularly an endoscope, with a sliding tube to accommodate a rotor and a rotor arranged in said sliding tube. Furthermore, the present application relates to a rotor positioning key for a rotor of a, particularly bistable, actuator. 
         [0004]    2. Prior Art 
         [0005]    An endoscope with a distally arranged objective is known from DE 196 18 355 C2, the image of which is forwarded to the proximal end by an image forwarder and that has at least one optical element like a lens group, which is shiftable in the direction of the optical axis for focussing and/or for changing the focal length by a microdrive, wherein the microdrive has at least one rotationally symmetrical axially movable sleeve, which surrounds and receives the lenses or respectively the optical element of the movable lens group and wherein the sleeve is made of a permanently magnetic material and is movable in a magnetic field, which is generated by a spool arrangement. In order to move and to hold the sleeve, an electromagnetic field is generated continuously. 
         [0006]    An endoscope with a distally radiating illumination device for a body cavity part to be observed and an image conductor is known from DE 1 253 407 B, which captures the illuminated image via an objective that is adjustable in the axial direction and directs it to an ocular or a camera, wherein the objective is adjustable for at least two image sharpness settings from one position into another position with respect to the distal end of an image conductor through electromagnetic manipulation of an objective mount serving as an anchor. At least one of the two positions is hereby evoked by a permanently present electromagnetic field and the other position by the effect of a spring. 
         [0007]    Moreover, an electromagnetic actuator for a surgical or medical instrument, in particular an endoscope, is described in DE 10 2011 006 814 A1. 
       SUMMARY 
       [0008]    An object is to improve the handling of an actuator for a surgical instrument in a simple manner. 
         [0009]    This object is solved through an actuator, particularly a bistable actuator, for a surgical instrument, particularly an endoscope, with a sliding tube to accommodate a rotor and a rotor arranged in said sliding tube, which is further developed in that the sliding tube has at one end a receiving cavity for a rotor positioning key, wherein the receiving cavity is designed such that, after the rotor positioning key has been positioned in the receiving cavity and after the rotor positioning key has been twisted in the receiving cavity, the rotor positioning key is releasably locked. 
         [0010]    When using a rotor positioning key, which is arrangeable in the receiving cavity of the sliding tube, the stroke of a rotor in the sliding tube of the actuator can be adjusted in a simple manner, since in the interaction between the receiving cavity and the rotor positioning key, the rotor positioning key is securely held on the end of the sliding tube, wherein the stroke of the rotor is determined by the thickness of the key head of the rotor positioning key. A fixed spacer element is hereby provided during the setting of the positioning travel of the rotor. After the receiving of the rotor positioning key in the receiving cavity, the rotor positioning key is twisted so that, after execution of the twist, the rotor positioning key is brought into a corresponding setting position for the rotor. 
         [0011]    For this, the receiving cavity has a rotary gate, which in the interaction with the rotor positioning key, ensures a twisting of the rotor positioning key and a locking of the key. The rotary gate thus has a function of a rotary guide device for the rotor positioning key. 
         [0012]    An actuator for a surgical or medical instrument, particularly an endoscope, is understood as a, preferably bistable, actuator. The electromagnetic actuator hereby has a stator and a displaceable rotor. The rotor is hereby located inside the sliding tube. In one embodiment, the rotor itself has at least one paramagnetic and/or ferromagnetic material, wherein the rotor is shiftable from a first position into a second position by supplying an electromagnetic field. The rotor is thereby held in a first position by a permanent magnetic field and, after being shifted into a second position, is held in the second position by a permanent magnetic field. 
         [0013]    Additional details about an electromagnetic, bistable actuator of a surgical or medical instrument are described in DE 10 2011 006 814 A1, wherein the disclosed content of this document is incorporated herein by reference in its entirety. 
         [0014]    Moreover, one embodiment of the actuator is characterized in that the receiving cavity has a stop for the rotor positioning key. A defined stop point for the rotor positioning key is hereby provided in the axial direction, i.e. the direction of movement of the rotor. 
         [0015]    Moreover, the receiving cavity of the sliding tube is adjusted in a shape-complementary manner and/or functionally complementary manner to the contour of a key head of the rotor positioning key. 
         [0016]    The receiving cavity thereby preferably has a non-round and/or star-shaped, in particular polygonal-like or polygonal, cross-sectional contour. 
         [0017]    In the interaction of the rotary gate of the sliding tube and of the rotor positioning key, which is arranged and rotated in the receiving cavity of the sliding tube, and due to the shape- and functionally complementary design of the receiving cavity and of the key head of the rotor positioning key interacting with the receiving cavity, an end position of the rotor in the sliding tube is provided as a stop position in a simple manner. The rotor positioning key is hereby rotated around its axis in the rotary gate provided for this purpose after arrangement in the receiving cavity, whereby, due to the projecting shape of the key head, the key head of the rotor positioning key is locked at a defined distance between the stop in the sliding tube and the end face of the rotor positioning key for the setting of the stroke length of the rotor in the sliding tube. 
         [0018]    After the insertion and the twisting of the rotor positioning key, the rotor in the sliding tube, if applicable together with a stopper or the like, is pressed in the sliding tube, with force against the stop surface of the locked key head, which faces the rotor. In this state, e.g. a stopper is then connected or respectively joined with the sliding tube e.g. through an adhesive process or the like. The rotor positioning key is subsequently rotated back in the receiving cavity in the rotary gate and removed from the receiving cavity so that space is created for the stroke of the rotor in the sliding tube. 
         [0019]    Moreover, the object is solved by a rotor positioning key for a rotor of a, particularly bistable, actuator, of a surgical instrument, particularly an endoscope, wherein the rotor positioning key is releasably lockable in a sliding tube of the actuator and is twistable in a rotary gate, in particular the receiving cavity. In particular, the sliding tube of the actuator is designed as described above. 
         [0020]    In a further development, the rotor positioning key preferably has an end-side, widened key head for arrangement and for insertion into the receiving cavity of the sliding tube or respectively into the rotary gate provided for the rotor positioning key, and a key shaft for twisting the rotor positioning key, preferably in the rotary gate. 
         [0021]    A secure arranging and guiding of the key head in the receiving cavity is thereby achieved, wherein the key head interacts with the receiving cavity of the sliding tube upon arrangement of the key head. The key head of the rotor positioning key is preferably designed in a non-round and/or star-shaped, particularly polygonal-like, manner. 
         [0022]    Moreover, the object is solved through use of a rotor positioning key described above for an actuator of a surgical instrument, in particular in combination with an actuator described above. For this, we refer expressly to the above explanations. 
         [0023]    Further characteristics will become apparent from the description of embodiments according to the invention together with the claims and the included drawings. Embodiments a can fulfil individual characteristics or a combination of several characteristics. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]    The invention is described below, without restricting the general idea of the invention, using exemplary embodiments with reference to the drawings, whereby we expressly refer to the drawings with regard to all details according to the invention that are not explained in greater detail in the text. The figures shown in: 
           [0025]      FIG. 1  illustrates a schematic sectional representation through a part of an endoscope with an actuator, 
           [0026]      FIG. 2  illustrates schematically a section of a sliding tube of an electromagnetic actuator; 
           [0027]      FIG. 3  illustrates schematically a perspective representation of a rotor positioning key according to the invention in a perspective view; 
           [0028]      FIG. 4  illustrates a top view of an N side of the sliding tube with rotor positioning key arranged in it. 
       
    
    
     DETAILED DESCRIPTION 
       [0029]    In the drawings, the same or similar types of elements and/or parts are provided with the same reference numbers so that a re-introduction is omitted. 
         [0030]      FIG. 1  shows a schematic sectional representation through a part of an endoscope with an actuator. The actuator can be arranged in a shaft (not shown) of an endoscope. In  FIG. 1 , the shaft of the endoscope would be arranged around the actuator, namely with a diameter which is slightly larger than the outer diameter of the distal end  18  of the sliding tube  11 . 
         [0031]    The sliding tube  11 , which can be made of a metal or plastic, wherein it is important here that it is made of non-magnetic materials, serves as a guide for the axially displaceable rotor  10 . The rotor  10 , designed as a displaceable element, can have for example a lens  13 , which is part of an objective, which also has lenses  14  and  15 , which are inserted into a locked holding element  12  and are correspondingly held. 
         [0032]    The locked holding element  12  is locked or respectively attached in the sliding tube  11  and defines a stop  16 . An additional stop  17  to the distal end is also defined by the sliding tube  11  through a collar inwards. In this exemplary embodiment according to  FIG. 1 , it is a rotationally symmetrical structure, in which an axially displaceable rotor  10  is provided. The axially displaceable rotor  10  can be displaced from a proximal position in  FIG. 1  to the left towards the stop  17  into a distal position. The displaceable element  10  is designed as a type of sleeve, which is made in particular of a magnetically soft material, such as a ferromagnetic material or respectively has this material. 
         [0033]    Besides being made of ferromagnetic and/or paramagnetic material, the displaceable rotor  10  can also have a friction-reducing coating on the surface, which is arranged towards the inside wall of the sliding tube  11 . 
         [0034]    The rotor  10  that is axially displaceable in the sliding tube  11  has a distal pole shoe and a proximal pole shoe, which interact with the magnetic field of the permanent magnets  20  and  21 , which are designed as rings and are arranged in a rotationally symmetrical manner around the longitudinal axis of the electromagnetic actuator. A first intermediate part  22  and a second intermediate part  23  made of paramagnetic or ferromagnetic material, which are also designed with pole shoes or as pole shoes, are provided between the permanent magnets  20  and  21 . The first intermediate part  22  and the second intermediate part  23  can also be one-piece, i.e. form a single intermediate part. 
         [0035]    Furthermore, a spool  24  is provided, which is surrounded to the outside by the first intermediate part  22  and the second intermediate part  23  and is surrounded to the inside except for the interruption by the sliding tube  11  also by paramagnetic and/or ferromagnetic material of the displaceable rotor  10 . A very strong strengthening of the electromagnetic field is hereby achieved. The stator  19  of the electromagnetic actuator consists mainly of the two permanent magnetic rings  20  and  21 , the two intermediate parts  22  and  23  and of the spool  24 . 
         [0036]      FIG. 2  shows schematically in a perspective view an end-side section of the sliding tube  11 , wherein the sliding tube  11  has a receiving cavity  30  on the end shown. The receiving cavity  30  has a non-round shaped inner contour as rotary gate, wherein the receiving cavity  30  interacts with the contour of a rotor positioning key. The receiving cavity  30  has for this on its circumference recesses  32  and undercuts  34  for the rotary gate, which are arranged at regular intervals in the circumferential direction of the sliding tube  11 . 
         [0037]    The undercuts  34  thereby form rear stops or respectively outside stops for the rotor positioning key after insertion of a rotor positioning key into the receiving cavity  30 . The recesses  32  and undercuts  34  arranged alternating in the circumferential direction are arranged evenly in the circumferential direction. In one embodiment, the recesses  32  and the undercuts  34  can hereby be arranged irregularly in the circumferential direction. 
         [0038]      FIG. 3  shows schematically in detail a perspective representation of a rotor positioning key  40  for the rotary gate of the receiving cavity. The rotor positioning key  40  has thereby a rotatable shaft  42 , on the end of which is arranged a widened key head  44 . The key head  44  is thereby designed in a star-shaped or a star-like manner. The key head  44  that is insertable into the receiving cavity has a thickness d, which corresponds to the stroke length of the rotor in the sliding tube  11  after adjustment of a rotor in the sliding tube  11 . The rotor positioning key  40  is hereby inserted into the receiving cavity  30  during the adjustment of the rotor arranged inside the sliding tube  11 , wherein the rotor positioning key  40  is twisted after arrangement of the rotor positioning key  40  in the receiving cavity  30 . The rotor positioning key  40  is thus releasably locked inside the sliding tube  11  for adjusting the stroke length of the rotor. 
         [0039]    The key head  44  has a non-round outer contour, wherein the outer contour of the key head  44  is designed in a star-like manner, wherein the shape of the key head  44  is designed in a shape-complementary manner to the arrangement of the recess  32  and the undercuts  34  of the receiving cavity  30  as well as the rotary gate of the receiving cavity. The rotor positioning key  40  is hereby inserted in an accurately fitting manner into the receiving cavity  30  during insertion of the key head  44  and is subsequently locked by twisting of the rotor positioning key so that the protrusions or respectively tongue-like projections of the key head  44  are arranged in the area of the undercuts  32 . 
         [0040]    In the case of this positioning of the rotor positioning key  40 , the rotor and a stopper arranged in the sliding tube  11  are subsequently pressed with force against the outer contact surface of the key head  44  facing the rotor so that the stopper is subsequently connected with the sliding tube, for example through adhesion. The rotor positioning key  40  is then rotated back and removed from the receiving cavity  30 . Space for the stroke of the rotor inside the sliding tube  11  is hereby created between the rotor and the open or respectively opened end of the sliding tube  11 . 
         [0041]      FIG. 4  shows schematically in a side view the arrangement of the key head  44  in the receiving cavity  30  in the twisted state or respectively locked state of the rotor positioning key  40 . The tongue-like protrusions of the key head  44  are hereby arranged behind the undercuts  34  of the receiving cavity  30 . 
         [0042]    In the exemplary embodiment shown in  FIG. 4 , the receiving cavity  30  has three abutment points or support points for the rotor positioning key  40 . A stop level or respectively abutment level for the key head  44  is hereby provided using the three support points. Within the framework of the invention, it is also conceivable that more than three support points are provided for the key head  44  through the receiving cavity. 
         [0043]    All named characteristics, including those taken from the drawings alone and also individual characteristics, which are disclosed in combination with other characteristics, are considered alone and in combination as essential for the invention. Embodiments according to the invention can be realized by individual characteristics, or a combination of several characteristics. 
       LIST OF REFERENCE NUMBERS 
       [0000]    
       
         
           
               10  Rotor 
               11  Sliding tube 
               12  Fixed holding element 
               13  Lens 
               14  Lens 
               15  Lens 
               16  Stop 
               17  Stop 
               18  Distal end 
               19  Stator 
               20  Permanent magnet 
               21  Permanent magnet 
               22  1st intermediate part 
               23  2nd intermediate part 
               24  Spool 
               30  Receiving cavity 
               32  Recess 
               34  Undercut 
               40  Rotor positioning key 
               42  Shaft 
               44  Key head 
             d Thickness of key head