TECHNICAL FIELD AND BACKGROUND OF THE INVENTION 
     The invention relates to an apparatus for actuating a variety of interchangeable surgical instruments, more particularly for anastomosis (i.e parting, closing and connecting) of hollow organs. 
     Known from U.S. Pat. No. 4,573,468 is a surgical suture stapler including a reusable unit made up of a handle part and shank part as well as a mountable disposable head unit. This instrument comprises a pistol-type handle part and a straight shank part which cannot be separated from each other. The shank part is configured as a rigid, straight tube. 
     A mountable disposable head unit in the form of the suture stapler comprising suture staples, a staple ejector, a circular scalpel, a mandrel as well as an anvil is secured to the distal end of the shank part by means of a bayonet lock or a threaded connector. 
     Known from U.S. Pat. No. 5,533,661 is a suture stapler in which neither the shank nor the head is separable from the handle part and shank part respectively. Merely an anvil and a pin can be separated from the shank part. Furthermore the handle part cannot be disassembled and the whole instrument is devised exclusively for once-only use. 
     The known suture stapler, like other non-reusable surgical instruments, has various disadvantages which have proved to be nuisance in actual practice, although not each and every one of these instruments has all of the disadvantages as listed in the following, they usually having, however, several of these disadvantages at the same time. 
     The known instruments generally are too heavy, some of these instruments requiring for their actuation excessive operating forces and/or failing to incorporate feedback information means, for example, in the form of “stapling or cut performed”. Non-reusable circular instruments involve high costs simply from the fact that they can only be used once and then need to be disposed of. 
     SUMMARY OF THE INVENTION 
     It is thus the object of the invention to design and implement an apparatus for actuating surgical instruments which is low-weight, requiring little force to operate and which more particularly is to be reused. 
     In an apparatus for actuating a variety of interchangeable surgical instruments in accordance with the invention a handle part is secured releasably and properly located to the proximal end of a shank part. Attached to the handle part is a pivotable toggle mechanism releasably in contact with the proximal end of a flexible, force-transmitting reciprocating part guidingly accommodated in the shank part. The proximal end of the reciprocating part is connected to an adjusting mechanism in the handle part. Connected to the distal end of the force-transmitting reciprocating part is a connector for producing a connection to a surgical instrument. Provided at the distal end of the reciprocating part is a push button fastener for attaching a housing of the surgical instrument whilst applied to the distal end of the flexible reciprocating part is a part transmitting an axial compressive force to the body of the surgical instrument. 
     In the apparatus of the invention the handle part may be disassembled for the purpose of cleaning/sterilization to advantage without requiring any tools. By means of a toggle mechanism provided on the handle part a higher force may be applied towards the end, for example, of a stapling action and excision so that a satisfactory tissue cut is reliably assured. 
     In the apparatus in accordance with the invention an adjusting mechanism permits to particular advantage a swift approximation, for example, of an anvil to a staple cartridge and in addition subsequently a vernier adjustment e.g. of a tissue gap. During approximation, i.e. movement of the anvil an axial adjustment is implemented which is transmitted via an internal pusher to an operating control on the handle part. For vernier adjustment a mechanism is provided which translates this axial movement into a rotary movement. This rotary movement is locked out during an operation, as a result of which the axial position of the adjusting mechanism is fixed in place. 
     Accordingly, in the apparatus in accordance with the invention the adjusting mechanism is automatically arrested in the vernier adjustment range and is thus unable to become displaced in performing the operation, for example, during a stapling action. A positive lock of the rotary movement enables very fine indexing of the vernier adjustment range to be achieved. 
     The shank part of the apparatus in accordance with the invention comprises a mechanism to transmit a predetermined force, for example. during a stapling action, as well as a predetermined travel, such as, for example, an adjustment travel for an anvil, whereby the force and the adjustment travel may be applied or implemented for both straight and single-axis bent shank tubes. 
     In apparatus in accordance with the invention comprises only two assemblies comprising a few elements suitable for reuse, simple to assemble locked in place and to disassemble, each of which is simple to clean and thus simple to resterilize. Via a push-button/mounting fastener designed for facilitated operation a variety of head units may be connected to the apparatus in accordance with the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will now be detained by way of preferred embodiments with reference to the attached drawings in which: 
     FIGS. 1 a  and  1   b  is each a schematic, perspective view of a preferred embodiment of a handle part as well as of a shank part released therefrom: 
     FIG. 2 a  is a plan view, not true to scale, of a mechanism in the shank part as well as 
     FIG. 2 b  is a magnified detail illustration of a partial portion of that as shown in FIG. 2 a;    
     FIG. 3 is a schematic illustration of an adjusting mechanism; 
     FIG. 4 is an axial section view of the handle part secured to the shank part with the operating control part actuated; 
     FIG. 5 is a axial section view, corresponding to that as shown in FIG. 4, of the handle part secured to the shank part with the operating control part non-actuated; 
     FIG. 6 is a perspective view of the handle and shank parts joined to each other and a fitted disposable head unit indicated schematically; 
     FIG. 7 a  is an axial section view through the end part of the shank part showing a connector for a mandrel and, for example, a staple cartridge; 
     FIG. 7 b  is a magnified illustration of a detail of the end part as shown in FIG. 7 a;    
     FIG. 7 c  is an illustration in perspective of the end part of the shank part and a receiving mount for the mandrel, 
     FIG. 7 d  is a magnified illustration in perspective of a push button fastener at the distal end of the shank part including a push button mechanism ssigned thereto at the proximal end of a staple cartridge; 
     FIG. 7 e  is an illustration showing a modified variant of the distal end of the shank part and one proximal end of a staple cartridge adapted thereto; 
     FIG. 8 a  illustrates a straight oriented, pliable shank tube, a shank tube bent to the right being indicated dashed: 
     FIG. 8 b  is a magnified section illustration of a detail of a distal shank tube end, and 
     FIG. 8 c  is an exploded view in perspective illustrating the component parts for controlling the shank tube. 
    
    
     DETAILED DESCRIPTION 
     Referring now FIGS. 1 a  to  3  there are illustrated partially in perspective the various assemblies, i.e. shank part assembly  1  (FIG. 1 a ), handle part assembly  2  (FIG. 1 b ), mechanism assembly  3  in the shank part  1  (FIGS. 2 a  and  2   b ) and adjusting mechanism assembly  4  (FIG.  3 ). 
     The following describes firstly the various elements of the handle part  2  as well as of the shank part  1 . The handle part  2  comprises a tubular housing  26 , a pivotable lever  21  as well as a leg  22 ; whereby lever  21  and leg  22  form together a toggle. 
     Referring now to FIG. 6 there is illustrated provided an indicator  252  configured as a window for verifying whether the adjusting mechanism  4  is in the vernier adjustment range, an indicator  251  for checking that the adjusting mechanism is arrested and a scale  253  for a set gap width. In addition an assembly groove  27  (see FIG. 4) is configured on the housing  26  to ensure proper location in fitting the shank part  1  to the distal end of the latter. The pivotable lever  21  is mounted pivotable by means of a pin  283  in two mounting pads  28 . The leg  22  is movingly connected to the lever  21  via a pin  221  (FIGS.  4  and  5 ). At the end facing away from the pin  221  the leg  22  comprises a transverse pin  222  (FIG. 4) producing a connection to the mechanism assembly  3  via an intersection groove (FIG. 2 a ) formed by a transverse groove  315  and a longitudinal groove  316  to a connector  31  of flexible reciprocating part  32 . 
     Referring now to FIGS. 1 a  and  1   b  there is illustrated that for assembly/disassembly the transverse pin  222  fixedly connected to the leg  22  is insertable and removable into/from the transverse groove  315  through tee-shaped windows  261  and  1111  configured in the housing  26  of the handle part  2  and equivalently in a connector  11  of the shank part  1 . 
     It is precisely then, when the toggle  21 ,  22  is fully open that the leg  22  may be inserted with its transverse pin  222  into the transverse groove  315  in the connector  31  through the tee-shaped windows  261 ,  1111 . During operation a narrow portion  1112  of the tee-shaped window  1111  prevents the leg  22  from springing out of place from the connector  31 . 
     During assembly/disassembly, toggle  21 ,  22  can only be opened further than as shown in FIG. 5 when as regards a cavity  281  (FIG. 4) a fastener nut  13  is not screwed onto a thread  262  of the housing  26 , as a result of which in assembly/disassembly the toggle  21 ,  22  may be oriented so that the transverse pin  222  locates within a wide portion  1113  of the tee-shaped window  1111  thus enabling the toggle  21 ,  22  to be separated from the connector  31  of the flexible reciprocating part  32 . 
     Via the pin  283  the lever  21  is movably or pivotably connected to the mounting pads  28  of the housing  26  between which lever  21  and leg  22  of the toggle can thus be moved. At the same time due to the configuration of the mounting pads  28  of lever  21  and leg  22  there is no risk of gripping occurring accidentally between lever  21  and leg  22 . 
     Integrated in the lever  21  is a lock  211  (see FIG. 5) preventing unwanted actuation of the toggle, a leg spring  212  relatching the lock  211 , for example, following implementation of a stapling action and having achieved the toggle position as shown in FIG. 5, 
     The shank part assembly  1  is fixedly connected to the proximal (i.e. facing the operator) end in the handle part assembly  2  and at the distal (i.e. facing away from the operator) end a staple cartridge  5  indicated merely schematically in FIG.  6  and not described in detail, for example, may be applied by snap-action noses  51  provided at the proximal end thereof of a push button mechanism via a push button fastener  14  as is evident from FIG. 7 d  on a magnified scale. 
     The shank part assembly  1  may comprise a pliable, bent shank tube  12 ′ (FIGS. 1 a  and  6 ) or also a straight, rigid shank tube  12  (FIGS. 4 and 5) and has furthermore a connector  11  connected to the corresponding shank tube  12  or  12 ′ as well as the fastener nut  13  freely rotatable on the latter. The connector  11  comprises a stop  111  (FIG. 4) for both the nut  12  and housing  26 . 
     For guiding and rotatively locking in place a middle part  41  of the adjusting mechanism  4  by means of a pin  413  protruding from the latter a longitudinal groove  115  is provided in the shank part  1 . In a tubular runway  117  the middle part  41  is coaxially guided by a circular-cylindrical raised face  412  (FIG. 5) and the connector  31  by a circular-cylindrical section  3192  (FIG. 2 a ). 
     The mechanism assembly  3  provided for transmitting a force and an axial movement along the shank tube  12  consists in all of three main components: the connector  31  accommodated mainly in the handle part  2 , the flexible reciprocating part  32  and two thin metal bodies  33  embedded in the latter (FIG. 2 b ) which due to their axial stiffness transmit an axial force. The flexible reciprocating part  32  guides the metal bodies  33  along the neutral fiber whilst permitting bending in a single axis due to its shell surface area comprising recesses  321  and circular-cylindrical sections  322 . 
     The force is transmitted at the distal end of the mechanism assembly  3  by a graduated pusher  34  (FIGS. 7 a  and  7   e ) as an axial compressive force to a corresponding component in a staple cartridge  5 , for example. At its distal end the pusher  34  comprises a section  341  having a corresponding large diameter so that in executing, for example, a stapling action the snap-action noses  51  of the push button fastener  14  (see FIG. 7 d ) are locked in place to prevent accidental opening by the forward displacement of the pusher  34  and the flexible reciprocating part  32  in connection therewith distally. The mechanism assembly  3  is configured tubular throughout and comprises a preferably central working passage  312  or  323  (guided along the neutral fiber) in which part of the adjusting mechanism  4  is movingly guided. 
     Guided on the cylindrical outer surface area  311  of the connector  31  is a spring  318  (FIGS.  4  and  5 ). The mechanism assembly  3  and adjusting mechanism assembly  4  are mutually oriented rotatively by a dowel pin  317  (FIG. 4) and a groove  411   a  (FIG.  5 ). The complete mechanism assembly  3  is pretensioned against an annular stopping surface area  116  by means of the spring  318  so that the toggle  21 ,  22  can be returned to the starting position as shown in FIG. 5 after implementation of a stapling action, for example. 
     For moving the mechanism assembly  3  relative to the shank part assembly  1  and handle part assembly  2  the transverse pin  222  of the leg  22  engages the transverse groove  315  in the connector  31 , as a result of which the axial force produced by the toggle  21 ,  22  is transmitted to the mechanism assembly  3 . 
     Sliding in the spacious working passage  312  is the middle part  41 . A stopping surface area  3191  of the connector  31  forms with a stopping surface area  112  of the connector  11  the travel limit of the mechanism  3 . A groove  313  (FIG. 2 b ) receives the force-transmitting metal bodies  33  which is fixedly connected to the connector  31  by rivets  314 . The metal bodies  33  are embedded in the flexible reciprocating part  32  and are thus guided along the neutral fiber of the shank tube  12 . 
     The flexible reciprocating part  32  comprises the working passage  323 , preferably arranged centrally, recesses  321  permitting flexing of the flexible reciprocating part  32  in complying with the bending of the shank tube, and circular-cylindrical sections  322  serving, on the one hand, guidance in both a straight and curved shank tube and, on the other, to prevent kinking of the metal bodies  33 . A good connection to the flexible reciprocating part  32  is assured by the perforation of the metal bodies  33 . 
     It is also possible to do away with the metal bodies  33  and to transmit a force exclusively via the flexible reciprocating part  32 . Preferably, further working passageways may be optionally incorporated in the flexible reciprocating part  32  along the neutral fiber of the curved shank tube  12  to provide the mechanism with additional functions, where necessary. 
     The adjusting mechanism  4  provides the operator with an operating control on the handle part  2  with the aid of which, for example, an anvil  7  may be retracted and extended. Mounted in the handle part  2  is a spindle  42  rotatively movable but axially defined by stops  422  and  423  relative to the connector  11  and the housing  26 . The spindle  42  is screwed into a threaded insert  416  of the middle part  41 . 
     Via rivets  453  a core  45 , acting as the thrust driving medium, is connected to the middle part  41 , this core comprising a force-transmitting metal body embedded in a flexible cylindrical body, preferably made of a plastics material, for guiding and protective purposes. By means of the core  45  the adjustment travel is transmitted from the handle part  2  along the shank tube  12  via the circumferential groove  461  (FIG. 7 b ) at joint  46 , for example, to a mandrel  6  and the anvil  7 . 
     The middle part  41  is rotatively defined by the pin  413  and the groove  115  relative to the joint  11 . The operating moment for the adjusting mechanism  4  is transmitted from a handwheel  43  via a pin  436  and a groove  425  to the spindle  43 . Pin  436  and groove  425  permit the handwheel  43  to be axially shifted by a predetermined travel relative to the spindle  42 . This movement is counteracted by a compression spring  44  (indicated merely by a winding) supported by the housing  26 . Turning the handwheel  43  produces a translatory movement of the middle part  41  as a result of which an anvil, for example, is adjusted. 
     In the last proximity portion of, for example, the anvil  7  relative to the staple cartridge S the pin  413  becomes visible in the indicator window  252  (FIG. 6) indicating, “STAPLE ON”, for example. A serration  471  of a latch  47  fixedly connected to the middle part  41  mates with the serration  431  of the handwheel  43 , therefore resulting in the adjusting mechanism  4  and thus, for example, the anvil adjustment being locked. 
     For a further adjustment the handwheel  43  needs to be pulled out from the housing  26  against the force of the compression spring  43  so that the serrations  431  and  471  no longer mate, the handwheel  43  then permitting further turning and, for example, a corresponding gap width setting via the scale  253  (FIG.  6 ). As soon as a desired gap width has been set, the handwheel can be released which will then snap back into place in the housing as urged by the compression spring  44 . The serrations  431  and  471  then re-arrest the adjusting mechanism  4  and a raised face  441  on the handwheel  43  is only to be seen in the housing window  251  when arresting has been done correctly (FIG.  6 ). 
     The adjustment travel is defined by the stopping surface areas  422  and  417  as well as by the length of the groove  115 . It is not until the adjusting mechanism is in the vernier adjustment range that the toggle  21 ,  22  can be operated, i.e. it not being until then that a stop  223  of the leg  22  is able to pivot through a slot  411  in the middle part  41 . 
     For connecting a head unit, for example a circular suture stapler, to the shank part  1  of the apparatus in accordance with the invention the following individual fasteners are provided: 
     1.The push button fastener  14  (FIG. 7 d ) connects the housing of a head unit via push buttons  51  seated on spring tabs with the shank tube  12  of the shank part  1 , the push buttons  51  engaging corresponding radial holes in the shank tube  12  of the shank part  1 . 
     2.A mountable connector  46  connects a body  6  of the head unit to the adjusting mechanism  4 , a circular raised face on the inner contour of the slotted tubular end of the body  6  engaging a corresponding circumferential groove  461  on the connector  46 . 
     Once the mandrel has been mounted on the connector  46  and travelled towards the instrument, locking to prevent accidental release occurs by the graduated pusher  34  preventing radial opening of the connection on the mandrel  6  by a corresponding fit. 
     3.The graduated pusher  34  transmits the operating force as an axial compressive force to the body  52  of-the head unit. 
     Referring now to FIG. 8 a  there is illustrated a shank tube  12 ″ controllably deflectable in a single plane, i.e. from a straight position as indicated by the bold line into a deflected position on the right as indicated by the broken line. The shank tube  12 ″ as shown in FIG. 8 a  may be fitted instead of an e.g. rigid, straight shank tube  12  as shown in FIGS. 4 and 5 to the handle part  2  which otherwise remains unchanged. 
     Making the adjustment into a deflected position is implementable, for example, by means of a rotating ring  15 ″ provided at the proximal end of the shank tube  12 ″, this rotating ring being integrated directly upstream of a nut  13  (not shown in FIG. 8 a ) on the connector  11 ″ and thus in the shank part, with no change to the handle part assembly. 
     The rotating ring  15 ″ is guided in a groove  150 ″ configured therein axially on an annular raised face  16 ″ of the shank tube  12  and comprises on the inside two opposing coupling links  151 ″ engaging noses  17 ″ protruding from the connectors  181 ″,  182 ″ and configured preferably cylindrical. The connectors  181 ″,  182 ″ are rotatively defined by noses  17 ″ and straight axial grooves  121 ″. 
     Turning the rotary grip  15 ″ moves the one connector  181 ″ proximally and the other connector  182 ″ distally; both connectors  181 ″,  182 ″ then covering the same distance in the opposite direction relative to the lower end  120 ″ of the shank tube  12 ″. It is due to this arrangement that the flexible shank tube  12 ″ is deformed elastically into more or less a circular arc in a portion in which indentations  122 ″ more or less optionally pliable are provided between webs  123 ″. In this arrangement the neutral fiber  125 ″ as indicated dot-dashed in FIG. 8 b  maintains a constant length. 
     Further evident from FIG. 8 c  are tractive driver means  191 ″ and  192 ″ secured at their proximal ends to the connectors  181 ″ and  182 ″ respectively and at their distal ends diametrally opposing the proximal end of the flexible shank tube  12 ″ (see FIG. 8 b ). 
     A sheath (not shown in FIGS. 8 a  to  8   c ) of the shank tube  12 ″ in the form of a tubing, for example, serves to cover the indentations  122 ′ of the shank tube to thus create a shank tube  12 ″ which is smooth inside and out. 
     The rotating ring  15 ″ is configured self-locking to safeguard against accidental rotation and thus a deflection of the shank tube  2 ″ (not shown in FIG. 8 c ) or it is provided with a breakaway lock (likewise not shown). To facilitate assembly the grooves  151 ″ configured skew in the rotating ring  15 ″ and serving as coupling links comprise a preferably axial groove orientation (not shown in FIG. 8 c ). 
     List of Reference Numerals 
       1  shank part assembly 
       11  connector 
       111  stop for  13  and  26   
       112  surface area of  11   
       1111  tee-shaped window in  11   
       1112  narrow portion 
       1113  wide portion 
       115  longitudinal groove 
       116  annular stopping surface area 
       117  tubular runway 
       12  straight shank tube 
       12 ′ shank tube bent in a single axis 
       12 ″ flexible shank tube 
       120 ″ end of  12 ″ 
       122 ′ indentation 
       123 ′ web 
       13  fastener nut 
       14  push button fastener for  5   
       15 ″ rotating ring 
       150 ″ groove 
       151 ″ groove 
       16 ″ annular raised face 
       17 ″ noses 
       181 ″ connector 
       182 ″ connector 
       191 ″ tractive driver means 
       192 ″ tractive driver means 
       2  handle part assembly 
       21  lever 
       211  lock 
       212  leg spring 
       22  leg 
       221  pin 
       222  connector 
       223  stop 
       251  adjusting mechanism checking indicator 
       252  window indicating “vernier adjustment range” 
       253  gap width scale 
       26  housing 
       261  tee-shaped window in  26   
       262  thread 
       27  assembly groove 
       28  mounting pads 
       281  cavity 
       282  thread 
       283  pin 
       3  mechanism assembly 
       31  connector for  32   
       311  cylindrical surface area of  31   
       312  working passage 
       313  groove 
       314  rivets 
       315  transverse groove 
       316  longitudinal groove 
       317  dowel pin 
       318  spring 
       3191  stopping surface area on  31   
       3192  cylindrical section of  31   
       32  flexible reciprocating part 
       321  recesses in  32   
       322  cylindrical sections of  32   
       323  working passage 
       33  force-transmitting metal bodies 
       34  graduated pusher 
       341  section of  34   
       4  adjusting mechanism assembly 
       41  middle part of  4   
       411  slot in  41   
       411   a  groove 
       412  cylindrical raised face 
       413  pin 
       416  threaded insert 
       417  face surface area 
       42  spindle 
       422  surface area 
       423  stop 
       425  groove 
       43  handwheel 
       431  serration 
       436  pin 
       44  compression spring 
       441  raised face 
       45  core 
       453  rivets 
       46  joint 
       461  transverse groove in  46   
       47  latch 
       471  serration on latch  47   
       5  staple cartridge 
       51  snap-action nose 
       52  body 
       6  mandrel 
       7  clincher insertion head
For actuating a variety of interchangeable surgical instruments, more particularly for hollow organ anastomosis, an apparatus comprises at the proximal end of a shank part a handle part ( 2) secured releasably and correctly positioned thereto. A pivotable toggle mechanism is fitted to the handle part, the pivotable toggle mechanism cooperating releasably with the proximal end of a flexible, force-transmitting reciprocating part guidingly accommodated in the shank part. The proximal end of the reciprocating part is connected to an adjusting mechanism in the handle part. At the distal end of the reciprocating part a connector for connecting a surgical instrument is provided. At the distal end of the shank part a connector is provided for connecting a housing of the surgical instrument. Fitted to the distal end of the flexible reciprocating part is a pusher transmitting an axial compression force to the body of the surgical instrument.