the following detailed description should be read with reference to the drawings , in which like elements in different drawings are identically numbered . the drawings , which are not necessarily to scale , depict selected preferred embodiments and are not intended to limit the scope of the invention . the detailed description illustrates by way of example , not by way of limitation , the principles of the invention . this description will clearly enable one skilled in the art to make and use the invention , and describes several embodiments , adaptations , variations , alternatives and uses of the invention , including what is presently believed to be the best mode of carrying out the invention . integrated in the housing interior of a hand piece 1 are all devices required to perform a vacuum biopsy ( fig1 ), so that no cables or lines are required going from the housing of the hand piece to other external supply devices . thus , the hand piece 1 constitutes a complete vacuum biopsy device , which is freely movable in all directions . from the distal part of the left end cover 6 protrudes the distal part of the hollow biopsy needle 2 with the cutting sheath 3 surrounding it coaxially , which is required to remove the tissue sample . usually , a coaxial cannula is placed in the tissue , into which the biopsy needle 2 with cutting sheath 3 is introduced . outside the right end cover 7 of the housing there is arranged a connection element 4 , e . g ., a transparent flexible hose , which connects the vacuum pressure - generating device 5 , arranged in parallel with the biopsy needle , to the interior cavity of the biopsy needle 2 . the hollow connection element 4 is situated in immediate proximity to the end cover 7 of the housing . the biopsy needle with cutting sheath and additional elements , arranged in a biopsy needle carrier 37 , forms together with the connection element 4 and the vacuum pressure - generating device 5 an element 20 , easily inserted or taken out at the top , which is replaced as necessary ( fig2 ). the housing cover 10 is opened for this purpose . as fig2 in particular shows , the biopsy device can be divided into parts which are firmly connected to the housing ( disinfected parts ) and a removable element 20 ( sterile part ). while the parts firmly connected to the housing are merely disinfected , the removable element 20 comes in a sterile package and can be replaced as necessary , especially for each new patient . in the sample embodiment described hereafter , the vacuum pressure - generating device is arranged in parallel with the biopsy needle . however , in the scope of the invention , the vacuum pressure - generating device can also be arranged lying in the axis of the biopsy needle or the hand piece ; neither does it require its own connection element , if for example it is mounted directly on the end of the biopsy needle . between the left and right end covers 6 , 7 of the housing is the lower piece 9 of the housing and a housing cover 10 which is hinged in the end covers of the housing , with a locking latch 11 . by means of tie rods or screws , which are partly screwed into a base block 8 , the lower piece 9 of the housing is clamped between the end covers 6 , 7 , or it is joined to the base block 8 . the housing cover 10 can swivel about an axis secured in the end covers 6 , 7 of the housing . the housing cover 10 is closed before the biopsy mechanism is used ; the inner contour of the housing cover corresponds to the outer contour of the biopsy needle carrier 37 , which will be described more precisely hereafter . approximately at the center of the interior space of the housing is arranged the base block 8 , which is firmly connected to the lower piece of the housing , for example , by fixation elements and / or by a screw connection . the base block 8 , which extends not only in the lengthwise axis from the middle to the left , but also across the entire transverse surface , is connected to the drive elements for the vacuum pressure - generating device 5 , the cutting sheath 3 and the cocking mechanism for the tension slide 28 , on which the biopsy needle carrier 37 is mounted . furthermore , the base block 8 has a holder 36 , open at the top , for the biopsy needle / cutting sheath , and an additional insert element 62 for the vacuum pressure - generating device . in order to specify the position of the individual elements , as well as the position of the individual parts , especially in the interior of the housing , a coordinate scale has been drawn in fig1 , the midpoint of the coordinates lying at the center of the base block 8 ( fig1 ). accordingly , for the following description and for the claims , movement indicated in the direction of the x - axis is considered left ( distal ) and movement indicated away from the x - axis is considered right ( proximal ). for the other coordinates , movement in the direction of the y - axis is considered top , movement away from the y - axis is considered bottom , movement in the direction of the z - axis is considered rear , and movement away from the z - axis is considered forward ( fig1 ). thus , the coordinate system divides the interior of the housing and the other references into left and right , forward and rear , and top and bottom . making reference to these remarks , in the bottom , front , left part of the housing interior are found the joint actuating mechanisms 106 for the cocking mechanism and the cutting sheath , and in the bottom , rear , left part of the housing is the actuating mechanism 105 ( fig1 ) for the vacuum pressure - generating device 5 . in the bottom right part is accommodated the energy supply for the actuating motors and the other electrical parts , such as for the control and / or monitoring elements ; preferably , batteries or a storage battery 111 are used for this , e . g ., a 7 . 2 v lithium ion battery , 1 ah . the forward , right , top interior space of the housing lying above the battery compartment is utilized mainly for the tension slide 28 with locking piece ( fig5 ); this is connected to a block 26 , which is part of the base block 8 . the battery compartment is sealed on top by a separation plate 114 . in the uppermost front part of the housing interior there is arranged a biopsy needle carrier 37 , which can be inserted into and taken out from the u - shaped insert holder 36 of the base block 8 , which is open at the top , and the bracket 40 arranged on either side of the tension slide 28 and pointing upward ; the biopsy needle / cutting sheath unit with actuating parts is movably mounted in this , extending for almost the entire length of the hand piece . this means that , in the uncocked state , the left end surface of the biopsy needle carrier 37 lies against the left end cover 6 of the housing , and in the cocked state the right end surface lies against the right end cover 7 . “ almost the entire length ” means that the biopsy needle carrier is at least shorter by the distance required in the interior of the housing for the cocking sequence . if the cocking distance of the tension slide is 20 mm , for example , the biopsy needle carrier must be able to move by this amount . in general , the cocking distance is between 15 and 25 mm , depending on the biopsy needle used . it is therefore advisable to design the interior for the longest possible cocking distance . the cocking device ( situated right front ) itself consists of a tension slide 28 , placed on a bolt 30 , the bolt screwing into the base block 8 . the bolt 30 has a spiral spring 31 surrounding it . the locking device ( see especially fig9 b and 10 b ) of the tension slide is secured to the block 26 . in the top , rear , right interior of the housing is accommodated the vacuum pressure - generating device 5 with parts of the actuator ; the actuating motor with reduction gearing for the vacuum pressure - generating device is located in the left , bottom , rear area of the housing interior . the hand piece , and also in particular the biopsy needle or the vacuum pressure - generating device , are not connected either by cable or hose lines to additional supply units situated outside of the housing hand piece . therefore , the mobility and maneuverability is not impaired either by lines or by cables . the housing cover , the bottom piece of the housing , the end covers of the housing and the base block consist preferably of aluminum . the hand piece 1 consists , as already specified , of a housing , which is formed from a housing lower piece 9 with side walls raised to different height , the housing cover 10 adapted to the lower piece of the housing with lengthwise movable locking latch 11 , and the two end covers 6 and 7 . the lower piece of the housing is joined to the two end covers by tie rods or screws , e . g ., made of iron , which are partly screwed directly into the base block 8 . the housing is around 200 mm in length , the end covers have approximately square cross section , roughly 40 × 40 mm ( fig2 ). the housing cover 10 can swivel about an axis 104 , which is secured in the end covers 6 , 7 ; boreholes 14 in the end covers are used for this . the dog 12 of the locking latch 11 can be pushed into the recess 45 of the base block 8 to close the housing cover . the left end cover 6 has , in the upper forward part , an upward open u - shaped passage 13 for the forward protruding part of the biopsy needle / cutting sheath 2 , 3 and the guide roller 81 mounted thereon . the rear end cover 7 of the housing has two upward open u - shaped passages 15 , 16 . the passage 15 corresponds to the passage 13 ; it receives the end of the plastic part 47 , with round cross section , mounted on the hollow biopsy needle . in passage 16 is inserted a connection piece 63 for the vacuum pressure - generating device ( fig2 ). an additional plastic part 112 , inserted in the plastic part 47 , has a plug 17 which is used to connect the connection element 4 to the outlet connector 64 of the vacuum pressure - generating device . the inner cavity of the biopsy needle is connected continuously to the cavity of the plunger / cylinder arrangement and the cavity of the vacuum pressure - generating device . the connections are configured such that neither can air get into the system from the outside nor can air flow out when excess pressure prevails ; thus , the connection points are air - tight . as fig6 shows in particular , a miniature switch 18 is integrated in the passage 16 of the right end cover 7 at the bottom side , whose switch pin 19 protrudes into the passage . as soon as the connector 63 of the vacuum pressure - generating device is inserted in the passage and the housing cover is closed , the switch pin 19 of the miniature switch 18 is pressed downward and the miniature switch 18 allows current to flow . terminals for hooking up a charger can be built into the passages 97 , 98 of the right end cover 7 . at the front side of the bottom piece 9 of the housing there is a surface 113 provided for the board with the operating and monitoring elements ( fig1 ). the board 57 secured to the housing is designed as an independent component , which is glued , for example , onto the surface 113 of the bottom piece 9 . this board 57 is connected by lines to other electronic components arranged in the housing , and to the power supply . the board contains in particular switches for the operation and diodes for the monitoring . the activating button 88 for mechanical triggering of the cocked tension slide protrudes through a recess 65 in the bottom piece of the housing and the board . when configuring the operating and monitoring elements consideration was given to the difference between the cocking sequence of the tension slide and the triggering of the tension slide , on the one hand , and the performance of the biopsy , such as the cutting out of the sample , as well as the removal of the sample with the ejection of the sample , on the other hand . accordingly , the activating button 88 ( trigger ) for the tension slide has been placed at the right and the cocking button 90 for cocking the tension slide is at left . the program button 89 for performing the biopsy is in the middle . it is necessary to press the program button for three functions . the first function , start or reset , is indicated by the reset diode 91 , while the sample removal diode 92 arranged underneath indicates the opening and closing of the sample removal chamber when removing the sample . the lowermost eject diode 93 indicates the ejection of the removed sample . the cocking diode 94 indicates the cocking of the tension slide ; the locking diode 95 indicates the locking of the tension slide . the battery charge diode 96 indicates the charge condition of the battery or storage battery . the diodes are switched so that the diode blinks while performing the particular sequence and after completion of the sequence the diode remains lit . when there are two possible choices , both diodes are lit . the operator is then free to make a choice . the mode of operation and possibility of control shall be examined more closely in detail when describing the sequence . symbols ( icons ) at the margin symbolize the individual processes . to improve the operating safety it may be advisable to outfit individual automated sequences with delay circuit . in particular , it has been found that the processes of “ cocking of the tension slide ” by pressing the cocking button 90 and “ ejection of sample ” by pressing the program button 89 are provided with delay circuits of around 1 . 2 - 1 . 5 seconds to improve the operating safety . furthermore , the operating safety is improved when the light - emitting diodes indicating the individual processes have different colors for processes outside and processes inside the tissue . a perspective representation of the base block 8 ( looking from the front in the direction of the x - axis ) is shown by fig8 a ; the base block 8 is shown from the rear in the x - axis by fig8 b ( both of them perspective views ). the base block 8 can be divided into two halves , looking in the lengthwise direction ; the front part serves to secure the joint actuation for the cutting sheath and tension slide , and also in its upper part to mount the biopsy needle carrier ( fig8 a ); the rear part serves to secure the actuation for the vacuum pressure - generating device and to mount one side of the vacuum pressure - generating device ( fig8 b ). between the two actuating motors 21 , 58 , beneath the center rib 87 , is arranged a central electronic board . the base block 8 has in its left front part a u - shaped space 24 , in which is installed a toothed roller 23 , driven by the gear motor 21 . for this , the take - off shaft of the gear motor is mounted or inserted in an opening in the wall 25 of the base block 8 . the toothed roller 23 is mounted on the take - off shaft and secured to it , for example , by means of a screw , so that it cannot turn or shift . at the other end , the toothed roller 23 is mounted in the wall 22 of the base block 8 . the actuating motor used is a dc motor with a speed of around 11000 rpm . the dc motor is connected to a planet gear with high reduction ratio , on whose take - off shaft the toothed roller 23 is mounted . an additional block 26 is molded on the wall 22 , pointing to the right , which accommodates both the swiveling double lever 33 for the locking process and also serves to fasten the bolt 30 for guiding the tension slide 28 . the bolt 30 is screwed into the threaded borehole 29 . during the cocking process , the tension slide 28 moves to the right on the bolt 30 and the separating plate 114 is arranged underneath . the spiral spring 31 arranged on the threaded bolt 30 is compressed during the cocking process . at one end , the spiral spring thrusts against an end piece 32 of the threaded bolt or directly against the end cover 7 of the housing ; the other end of the spiral spring thrusts against the end of the guide borehole 115 of the tension slide . the tension slide 28 moves on the threaded bolt and the separating plate 114 and is thus prevented from twisting . one arm 99 of the double - arm lever 33 of the locking device engages with a groove 27 of the tension slide 28 ( fig9 a and 10 a ). the locking device , integrated in the block 26 of the base block 8 , consists of the double - arm lever 33 , which can swivel about an upright axis 35 ( looking in the y - axis ) by means of a compression spring 34 . the axis 35 , an upright pin , is secured in the boreholes 38 of the base block . in the uncocked condition , the part 99 of the double - arm lever lies in the groove 27 of the tension slide ; the compressed spring 34 acts on the part 100 of the lever to press the locking button 88 outward ( forward ). as soon as the part 99 of the double - arm lever can engage in the recess 82 of the tension slide , the activating button 88 is pressed outward . the tension slide is locked by the locking of the lever part 99 in the cocked condition and can now be triggered when necessary with the activating button 88 . since the tension slide is advisedly made of plastic , it has proven advisable to employ a metal part 83 in the recess , so as not to damage the plastic , since the double - arm lever is made of metal . unlike the removable element 20 , the hand piece 1 with replaced insertion element can be used repeatedly . the cocking distance corresponds to the depth of penetration of the biopsy needle into the tissue . hence , the length of the lever 99 likewise corresponds to the cocking distance . since the depth of penetration is generally between 15 and 25 mm , the same hand piece 1 can be used for different depth of penetration by appropriately configuring the length of the lever 99 and changing the setpoints of the control system . the tension slide 28 , which adjoins the block 26 , is arranged at equal height and is roughly equal in cross section . on its top side , the tension slide has two brackets 40 . the upward pointing surface 41 of the tension slide , as well as the upward pointing surface 44 of the block 26 , and the upward pointing surface of the extension 42 of the basic block 8 , together form a planar bearing surface for the lower sliding surface 43 of the biopsy needle carrier 37 mounted thereon . the biopsy needle carrier is made of plastic . as the tension slide is moved from the starting uncocked condition ( fig9 a ) to the cocked condition ( fig1 a ), i . e ., to the right , the biopsy needle carrier 37 held by the brackets 40 slides across the surface 42 and 44 . it is also conceivable that the sliding surfaces are configured not planar , as in the sample embodiment , but instead have specially configured sliding surfaces ; the important thing is that the biopsy needle carrier 37 can slide easily and straight on the sliding surface and the biopsy needle can penetrate straight into the tissue , or tumor , after triggering the activation button 88 . therefore , the upper outer contour of the biopsy needle carrier is also configured correspondingly to the inner contour of the housing cover and has only slight play relative to the housing cover in order to prevent the biopsy needle from deviating upward . above the u - shaped space 24 for the toothed roller 23 , at the height of the sliding surface 42 , the basic block 8 has a u - shaped upwardly open holder 36 , for inserting the biopsy needle / cutting sheath among other things . this holder serves primarily as a radial thrust bearing , i . e ., as a prop for the actuating part connected to the cutting sheath , the gear 74 , or the plastic disk 78 , in order to bring the tension slide into its cocked position by means of the actuating device 106 , as shall be described afterwards . in the upper rear part of the base block there is provided another u - shaped insert element 62 , in which the free end 61 of the threaded spindle of the vacuum pressure - generating device 5 is inserted . in the middle , top , of the base block 8 is the recess 45 , into which the dog 12 of the locking latch 11 of the housing cover is forced . a cover 46 arranged on the base block 8 , pointing to the left , separates the space of the actuating motors and the board from the upper left part of the housing interior , which is used primarily to keep the exchangeable biopsy needle carrier 37 , including biopsy needle and cutting sheath . the cover 46 protects the electric gear motors and the board against dirt . the board for the electronics lies between the actuating motors and underneath the middle rib . fig2 shows the biopsy needle carrier 37 , which can be inserted into the brackets 40 of the tension slide 28 with biopsy needle 2 and cutting sheath 3 , as well as other parts . the hollow , round circular biopsy needle 2 has a needle tip 70 , which adjoins the sample removal chamber 71 ( fig1 a - 11 e ). the biopsy needle 2 , which is round in cross section , is surrounded by a coaxially arranged cutting sheath 3 , round in cross section , having a cutting edge 72 at its left end , facing the sample removal chamber , which serves to cut out the tissue sample after the biopsy needle is introduced ( with sample removal chamber closed ) and after the sample removal chamber is opened and the sample is sucked into the sample removal chamber . the cutting edge preferably stands perpendicular to the lengthwise axis of biopsy needle and cutting sheath . the cutting process occurs by rotation and simultaneous lengthwise displacement of the cutting sheath by means of the threaded spindle drive . it is also conceivable that the motion occurs not continuously , but stepwise or vibrating , i . e ., the feed process moves back and forth with short intervals . at the other , proximal end of the cutting sheath , away from the cutting edge 72 , there is fastened a threaded spindle casing 73 with a gear 74 arranged at the end face of the threaded spindle casing . the threaded spindle casing with gear is arranged on the cutting sheath and prevented from turning and shifting . the threaded spindle cooperates with a threaded spindle nut 75 , which is firmly press - fitted in the biopsy needle carrier 37 . the gear 74 lies to the left , i . e ., before the spindle casing begins . when the threaded spindle casing is turned by means of the gear 74 , the cutting sheath is rotated and shifted in lengthwise direction along the biopsy needle 2 . the gear 74 at the left end of the threaded spindle engages with the toothed roller 23 after the biopsy needle carrier is inserted in the brackets 40 . so as to allow for inserting the biopsy needle carrier 37 into the brackets of the tension slide when the slide is not cocked ( fig2 ), the biopsy needle carrier has two plane parallel recesses 77 . when the sliding surface of the biopsy needle carrier 37 is placed on the surfaces 41 , 42 and 44 , at the same time the cutting sheath is inserted in the holder 36 of the base block 8 . to improve the turning of the spindle drive , especially when the holder 36 is used to support the cocking of the tension slide , a plastic disk 78 can be inserted at the left side of the gear , being provided with a slight cone . when the biopsy needle carrier is correctly inserted , it slides to the right by the sliding surface 43 over the surfaces 42 and 41 when the tension slide is cocked . since the specimen removal chamber is only closed after inserting the biopsy needle carrier , the gear 74 bears against the holder 36 . now , if the toothed roller 23 is driven further in the same direction , the threaded spindle drive will screw the tension slide to the right along the biopsy needle carrier , until it locks ; the biopsy needle will be pulled inward , while the cutting sheath remains in its position . after the locking , the cutting sheath protrudes beyond the tip of the biopsy needle . therefore , after the locking of the tension slide , the cutting sheath is rotated back to the starting position ( opposite direction of rotation ); the gear 74 will move from left to right in the toothed roller . after releasing of the tension slide , the biopsy needle / cutting sheath with gear slides back to the left with the biopsy needle carrier . now , the cutting sheath can again be moved to the right in order to open the sample removal chamber . the right end of the cutting sheath is connected to the hollow biopsy needle by a seal element 76 , able to move in rotation , but air - tight , so that neither air can get in between biopsy needle and the cutting sheath coaxially surrounding it , nor can air escape during excess pressure . on the right end of the biopsy needle 2 is mounted air - tight a round , likewise hollow plastic part 47 , being frictionally joined to the biopsy needle . the plastic part 47 has a bearing element 49 at its left end , which is press - fitted into the biopsy needle carrier ; at its right end , protruding from the hand piece 1 , there is inserted another plastic part 112 , which can turn relative to the plastic part 47 and the biopsy needle 2 . between biopsy needle and plastic part 112 there is inserted an o - ring seal . the plastic part has a plug 17 at its right end , onto which the connection element 4 is placed air - tight . there is also a knurled disk 80 on the right part , protruding from the biopsy needle carrier and the housing , by which , when rotated , the position of the sample removal chamber can be adjusted radially , without altering the position of the cutting sheath . one rotation of the biopsy needle involves only one rotation of the sample removal chamber and , thus , the sample removal device . the plastic part 47 with biopsy needle and cutting sheath is press - fitted into the biopsy needle carrier with the bearing element 49 and the threaded spindle nut 75 . the biopsy needle can rotate in the biopsy needle carrier and is mounted in the cutting sheath by the bearing element 49 and its narrow guide in the cutting sheath , and it can shift in the lengthwise axis with the biopsy needle carrier . as described above , the cutting sheath is axially movable by rotation relative to the biopsy needle . to the right of the bearing element 49 a polygon 50 is arranged on the plastic part , which can lock with the biopsy needle carrier by tension , so that the sample removal chamber of the biopsy needle can be brought into the most favorable position for the biopsy removal and held there by means of the knurled disk 80 . details of the sample removal chamber and the tip of the biopsy needle are represented in fig1 a - 11 e . the sample removal chamber 71 adjoining the needle tip 70 is open from above for approximately 25 % of its cross section . the cutting edges can be ground or sharpened . the sample removal chamber is between approximately 15 and 25 mm in length . it adjoins the cavity of the biopsy needle . at the transition , ie ., the right end of the sample removal chamber , the cross section of the cavity of the biopsy needle is closed between approximately 50 % and 75 % by a narrowing , e . g ., a stopper 79 ( fig1 b - 11 e ). the height of the stopper is chosen such that it extends downward past the recess of the sample removal chamber . in this way , the vacuum will especially draw in the tissue sample through the continuous opening of the sample removal chamber and bring the tissue sample up against the wall of the sample removal chamber . when there is excess pressure in the cavity of the biopsy needle , the narrowing or stopper has a pressure boosting effect . the stopper has roughly the length of 10 mm and is glued or welded into the cavity . when using laser welding , it has proven to be advantageous to make the left side of the stopper thin for a short length , around 2 mm , by removing material at the end surface . as a result , in this region at the end surface the tube of the biopsy needle is welded to the end surface of the stopper and is air - tight at the end surface . the stopper can also be of shorter length , as long as the same effect is achieved . thus , the stopper can also be replaced by a lip or dog of approximately the same height . the important thing is that the narrowing is configured such that the vacuum is brought to bear primarily from the bottom in the sample removal chamber , so that the sample clings to the wall of the sample removal chamber during the cutting process and does not change in length . it has also proven to be advantageous to provide additional fixation means on the sample removal wall . the suctioning of the sample from the bottom into the sample removal chamber produces , first , a high fill ratio of the sample removal chamber and , second , especially thanks to its configuration , a good fixation of the sample on the wall . since the cutting sheath separates the sample at the outside of the biopsy needle , this firm suctioning of the sample into the interior is also preserved during the separation process . furthermore , thanks to the cutting sheath arranged on the outside , thanks to the vacuum applied , no tissue is suctioned into the hollow cutting sheath and thus the tissue cannot get twisted or turned by the rotating lengthwise movement of the cutting sheath , as it is held fast in the interior of the cutting sheath . this improves the quality of the sample , since the pathologist obtains original material corresponding to the cross section of the cut and not being twisted or deformed . when the sample is ejected under pressure , a complete cleaning of the sample removal chamber occurs in addition through the stopper 79 , so that no commingling occurs when used repeatedly . since the vacuum generating device is used at the same time as a pressure generating device , the entire cavity is cleaned , especially that of the needle . fig1 shows the drive and the installation of the vacuum pressure - generating device 5 ( view from the rear , i . e ., opposite the z - axis , housing cover and lower housing piece left out ). in the upper , rear , right region , the vacuum pressure - generating device 5 is arranged as a piston / cylinder unit 69 . it consists of a syringe body 52 with threaded spindle 53 arranged inside , at whose end facing the syringe bottom 51 there is fastened a plunger 54 with seal elements — as is commonly known with syringes ( fig1 a - 14 d ). at the end of the syringe body 52 facing the base block 8 , a threaded spindle nut 48 is arranged on the threaded spindle with a gear 55 formed at the circumference . the threaded spindle nut has one or more thread turns . the threaded spindle 53 interacts with the threaded spindle nut 48 . the spindle has a pitch of around 5 mm per turn , so that at each rotation the plunger is moved out from the syringe body by a precisely defined amount , i . e ., away from the syringe bottom 51 , or toward the syringe bottom , depending on the direction of turning . the toothed crown 55 arranged on the circumference of the threaded spindle nut meshes with the drive pinion 56 , which is fastened on the take - off shaft of the dc gear motor 58 . the take - off shaft of the dc gear motor 58 is mounted in the base block 8 ; for this , the take - off shaft is inserted into the transverse plate 59 of the base block . when the dc gear motor 58 is activated , the plunger is moved toward the syringe bottom or in the direction of the base block 8 , depending on the direction of turning . the drive motor used is likewise a dc motor with high speed , connected to a planet transmission with high reduction ratio . it corresponds to the motor already described for the cocking mechanism . the plunger 54 is configured in familiar fashion as a syringe plunger . the syringe body made from plastic , being a cylinder with a bottom , is transparent . in order to prevent a twisting of the threaded spindle 53 upon actuation of the threaded spindle nut , the two opposite surfaces 60 of the threaded spindle are planer in configuration ( fig1 d ). the threaded spindle is inserted into the insert element by its free end . the spacing between the surfaces of the threaded spindle corresponds to the width of the u - shaped insert element 62 of the base block 8 . there is only slight play between the u - shaped cross section of the insert element and the spindle surfaces at either end . the threaded spindle nut thrusts against the base block . in order to prevent the syringe body 52 from sliding out upon turning of the threaded spindle nut , the bearing surface at the base block 8 is slightly conical toward the bottom . the connection piece 63 of the syringe body 52 is inserted into the passage 16 of the right end cover 7 so that the syringe body is held in roughly horizontal position . in order to make the threaded spindle easy to turn , the threaded spindle nut with toothed crown has a chamfer 66 around 1 . 5 mm in thickness at the side facing the base block . since , furthermore , the surface of the rib 59 on the base block 8 , which interacts with the chamfer 66 of the threaded spindle nut 48 , is inclined from top to bottom , the vacuum pressure - generating device is pulled downward during operation . to create a sufficient vacuum of around 200 hph in the sample removal chamber , for example , when using a biopsy needle with length of around 250 mm and an internal diameter of the hollow biopsy needle of around 5 mm , one uses a syringe body for 20 ml with a length of around 90 mm . in order to be able to use the syringe body also as a pressure generator , a ventilation opening 67 of around 1 . 5 mm diameter , for example , is provided after around ¾ of its length , corresponding to the stroke for producing the vacuum ( position per fig1 b ). if the syringe plunger is moved beyond the ventilation opening 67 ( fig1 c )— when the vacuum is no longer required — intake of air ( atmospheric pressure ) through the ventilation opening 67 will dissipate the previously established vacuum in the hollow biopsy needle . if , then , the direction of turning of the gear motor is reversed , the vacuum pressure - generating device will build up an excess pressure in the system by retraction of the plunger ( toward the bottom of the syringe ), which brings about the ejection of the tissue sample after opening the sample removal chamber . moreover , the pressurized air will clean not only the sample removal chamber , but also in particular the inside of the biopsy needle . the stopper narrowing the cavity of the needle will make it difficult or entirely prevent tissue parts from getting into the cavity of the biopsy needle . the narrowing of the needle cavity by the stopper 79 will increase the pressure at the sample removal chamber and thereby improve the ejection of the sample , even when the sample removal chamber is half open . the handling of the biopsy mechanism shall now be explained more fully . the removable insert element 20 , comprising a vacuum pressure - generating device , elastic connection element , biopsy needle carrier with needle and cutting sheath and additional elements connected to it , also contains a guide roller 81 mounted on the needle . this unit , including an insert aid , comes in a sterile package . the plunger 54 in the syringe body 52 comes slightly ( 1 - 2 mm ) lifted up from the syringe bottom , the sample removal chamber 71 of the biopsy needle 2 is open so that one can make a visual inspection of the chamber prior to inserting . after opening the housing cover 10 , the carrier element 37 , including biopsy needle 2 , cutting mechanism 3 , and other parts connected with it , such as the vacuum pressure - generating device 5 hooked up to the connection element 4 , is inserted into the connection element provided for this ( fig2 ). during the insertion process , one must make sure that the gear 74 engages with the teeth of the toothed roller 23 ; the cutting sheath is inserted from above into the u - shaped holder 36 , and at the same time the brackets 40 of the tension slide are introduced into the recesses 77 of the carrier element ; the guide roller 81 is inserted in the passage 13 , so that the flanks 101 and 102 embrace the left end cover 6 . the cutting sheath is mounted in the guide roller , able to move lengthwise and turn freely ; the guide roller itself , however , can no longer move relative to the cutting sheath after being inserted in the left end cover 6 . the vacuum pressure - generating device is then inserted at one end into the upward - open insert element 62 of the base block 8 by its free end 61 and at the other end into the u - shaped , upward - open passage 16 by the connection piece 63 . the connection piece 63 lies above the switch pin 19 . since the insert element at the base block has a clear width which just allows the inserting of the threaded spindle provided with surfaces 60 at either end , the threaded spindle is held in the insert element , secure from turning . the toothed crown 55 of the threaded spindle nut 48 engages with the take - off pinion 56 of the gear motor after being inserted . the spacing between the base block at one end and the housing end cover 7 at the other is maintained so that syringe body 52 with the threaded spindle nut 48 placed on the syringe body has just enough room . the unit formed by the syringe body and the mounted gear is held in this way so that it cannot shift axially . after being inserted , the vacuum pressure - generating device lies parallel to the biopsy needle carrier ; the connection element describes an arc of around 180 °. it should further be noted that the inserting is done when the tension slide is not cocked ; this means that the gear 74 engages at the right end of the toothed roller with the sample removal chamber open ( fig3 ). after being properly inserted , the housing cover can be closed . to facilitate the inserting process , an insert aid can be used . when the housing cover is closed , the connection piece 63 is forced downward and activates the miniature switch by the switch pin 19 built into the end cover of the housing . this activates the electrical system , which is indicated by blinking of the reset diode 91 on the front side of the hand piece 1 . the reset diode at first blinks green , which means that the positioning of the individual elements , i e ., the inserting process , is not yet finished ; the dc gear motor 21 must first close the sample removal chamber 71 with the cutting sheath 3 ( the sample removal chamber was partly opened during the inserting ). this occurs by twisting the threaded casing connected to the cutting sheath . the cutting sheath moves to the left until the gear 74 comes to bear against the inside of the holder 36 . after closing the sample removal chamber , the plastic disk 78 bears against the holder 36 ( inside ). during this process , or before or after it , the dc gear motor 58 brings the syringe plunger 54 to bear against the syringe bottom 51 . after the starting positions are reached for the vacuum pressure - generating device and the biopsy needle / cutting sheath , the cocking diode 94 and the sample removal diode 92 light up green , and the reset diode goes out . the operator must now decide whether to initiate the cocking of the tension slide or to remove an additional sample , e . g ., because he has already previously removed one tissue sample . if the operator presses the cocking button 90 , the cocking of the tension slide is initiated ; the cocking diode blinks green , the sample removal diode 92 goes out . by pressing the cocking button , the electrical dc gear motor 21 receives current and the dc gear motor actuates the toothed roller 23 . the gear 74 meshing with the toothed roller 23 turns the spindle shaft and at the same time the cutting sheath 3 connected to it . since the spindle nut 75 is press - fitted in the biopsy needle carrier 37 and the gear 74 is supported by the plastic disk 78 against the holder 36 , which is firmly connected to the housing by the base block 8 , the turning of the threaded spindle casing 73 has the effect of moving the biopsy needle carrier to the right . at the same time , the biopsy needle 2 connected to the biopsy needle carrier by the bearing element 49 is carried along , resulting in the tip of the biopsy needle moving into the cutting sheath . the biopsy needle carrier 37 is moved to the right by the recess / bracket connection of the tension slide against the action of the spiral spring 31 until the lever 33 of the locking element is forced into the recess 82 of the tension slide by the spring 34 . the tension slide is locked in this position . the gear motor receives the control command that the locking position has been reached , e . g ., via a photocell installed in the sliding surface of the cover plate , which interacts with the retracted biopsy needle carrier ; the direction of turning of the motor is reversed and the cutting sheath is turned back to the right by the amount that the cutting sheath had moved beyond the tip of the biopsy needle by the movement of the tension slide and the biopsy needle . at the end of this step , the cutting sheath completely closes the sample removal chamber ( fig1 d ), as at the start of the cocking process . the locking diode 95 lights up green ; the blinking of the cocking diode 94 goes out . so as to reduce the friction between gear and support element during the cocking process , the plastic disk 78 is arranged between gear 74 and holder 36 . now , the biopsy needle of the biopsy mechanism is inserted , for example , in a previously mounted coaxial cannula . the proximal end of the mounted coaxial cannula receives a seal , designed so that it seals off the space between cutting sheath and cannula , on the one hand , and allows an easy insertion of the biopsy needle with cutting sheath , on the other . the seal ring prevents air from the outside getting sucked in through the space between cannula and cutting sheath . the seal ring likewise prevents fluid ( cytological material ) from escaping after the biopsy needle is introduced or inserted . thus , the possibility of the disinfected hand piece 1 getting dirty is nearly precluded ; on the other hand , the flank 101 of the sterile guide roller 81 prevents the sterile cannula from getting dirty by reason of the hand piece 1 . the tip of the biopsy needle is brought up in the cannula to the tumor and , after being correctly positioned , thrust into the tumor . the shot is triggered by pressing the activation button 88 . this has the result of swiveling the double - arm lever 33 about the axis 35 to release the tension slide . the tension slide is hurled to the left by spring action . the sample removal diode lights up green , the cocking diode goes out . by operating the program button 89 , the sample removal sequence is enabled ; the sample removal diode 92 blinks green . at first , the dc gear motor 58 will activate the vacuum pressure - generating device . the plunger of the vacuum pressure - generating device is moved in the direction of the base block , i . e ., away from the bottom of the syringe , until it reaches a position just before clearing the ventilation borehole 67 ( fig1 b ). the vacuum is generated in the system . after reaching its end position , the system activates the motor 21 , the cutting sheath which closes the sample removal chamber is opened via the gear / spindle drive . during the opening process , the partial vacuum prevailing in the system sucks in the tissue and any cytological fluid ( cytological material ) into the sample removal chamber . cytological fluid will also flow thanks to the vacuum into the biopsy needle cavity and the vacuum pressure - generating device . it has proven to be advantageous to direct the partial vacuum by the stopper 79 primarily at the lower region , the lower side , of the sample removal chamber , and the stopper 79 will prevent or impede tissue from getting into the biopsy hollow needle . when the sample removal chamber is fully open — the tissue sample is accommodated in the sample removal chamber — the gear motor 21 is reversed and the sample removal chamber is closed . by turning the cutting sheath , the tissue is separated by the cutting edge 72 of the sheath 3 during the closing process . in order to reliably cut through the tissue filaments , it is advantageous to move the cutting sheath 3 beyond the distal end of the sample removal chamber ( around 2 mm ) in order to accomplish this , it is only necessary to program accordingly the microprocessor where the control data is kept . because of the special configuration of the sample removal chamber and thanks to the vacuum applied , the tissue sample is held in the chamber without torsion , so that the tissue sample is not twisted or turned by the rotating and lengthwise movable cutting sheath 3 which surrounds the biopsy needle on the outside , as described . after the sample removal chamber is closed , the dc gear motor is activated for the vacuum generating unit 5 . the plunger 54 is first retracted far enough to clear the ventilation opening ( fig1 c ). after the vacuum is dissipated in the system , the plunger travels toward the vacuum bottom until the ventilation borehole is again closed , in order to prevent the outflow of bodily fluid ( cytological fluid ). the blinking of the sample removal diode 92 goes out . the ejection diode 93 lights up green . the biopsy needle with closed sample chamber is extracted from the cannula . after the removal of the biopsy unit and providing a vessel to receive the tissue sample and fluid , the program button 89 is again operated and the ejection diode 93 starts to blink . at first , the gear motor 21 of the cutting sheath is operated to open the sample removal chamber roughly halfway . after this , the dc gear motor 58 of the vacuum pressure - generating device is activated . the turning direction of the dc gear motor 58 remains and the threaded spindle 53 with plunger moves in the direction of the syringe bottom , so that now an excess pressure is created in the system . the plunger travels up to the plunger bottom , and the actuating motor 58 is deactivated . the gear motor 21 moves the cutting sheath back across the sample removal chamber after the plunger has reached the plunger bottom . thanks to the excess pressure built up in the system , the sample is forced out under pressure into a waiting laboratory vessel even when the sample removal chamber is halfway open , and at the same time the cavity of the vacuum pressure - generating device , the biopsy needle and the sample removal chamber is cleared of tissue particles and fluid . the ejection of the sample when the sample removal chamber is around halfway open is so that the ejection of the tissue sample is assured and the tissue sample does not fall back into the chamber as a result of premature dissipation of the excess pressure . the narrowing of the cavity of the biopsy needle by the stopper 79 , which prevents or impedes tissue from getting into the cavity of the biopsy needle , proves to be especially advantageous when removing the sample , since the narrower cross section boosts the ejection pressure . the best ejection results were therefore achieved with the sample removal chamber halfway open ; i . e ., the cutting sheath clears half of the sample removal chamber . the excess pressure also forces tissue fluid out of the sample removal chamber and cleans it . after the sample removal chamber is fully open , the removal and cleaning is finished , and the ejection diode goes out . the reset diode 91 lights up green . if no further samples are to be removed now , the housing cover is opened and the removable element 20 is taken out . when the housing cover 10 is opened , the system is deactivated by the miniature switch 18 . however , if an additional sample is to be taken from the same tissue environment , the operator presses the program button 89 and the reset diode 91 starts to blink . the vacuum pressure - generating device , as well as the cutting sheath , are again adjusted as described . at the end of the process , the reset diode 91 goes out and the sample removal diode lights up . the next steps of the process occur in the sequence already described . the process can be repeated as often as desired . at the end , the operator need only decide whether to take another sample or to conclude the sampling and open the housing cover . as already described , in order to enhance the operating safety , a delay circuit can be provided for individual steps such as “ cocking ” and “ ejection of sample ”. furthermore , the light - emitting diodes can have different colors , so that one can distinguish between work in the tissue and that outside the tissue . if it is required to take the sample from a location of the tumor that does not lie directly above or at the sample removal chamber after being inserted , i . e ., it lies to the side , the position of the sample removal chamber 71 can be turned by means of the knurled disk 80 . so that the operator can recognize this radial positioning of the sample removal chamber , a marking in the form of a notch 119 is made on the knurled disk , pointing upward when the opening of the sample removal chamber points upward . the biopsy needle is fixed in the particular position by the surfaces of the polygon 50 and the elastic forces in the carrier piece . the sampling process is the same as already described . after completion of the biopsy , the interchangeable element 20 ( vacuum / pressure device , biopsy needle / cutting device with all elements arranged on it ) is removed from the top after releasing the cover . to make it impossible to open the housing when the tension slide is cocked , a safety tab 84 is arranged on the biopsy needle carrier , which bears against the left end surface 85 of the closure mechanism in the cocked condition . in this way , the closure mechanism , movable in the x - axis , can no longer be moved to the left into the open position and thus the dog 12 can no longer be taken out from the recess 45 . on the other hand , the housing cover also cannot be closed if the carrier unit has been inserted in the cocked condition , since the safety tab prevents the latch from being introduced into its designated space . the surface 85 of the latch adjoins the safety tab . the battery charge diode 96 is turned off as soon as the housing cover is opened . when the cover is closed and the insert element 20 is installed , the battery charge diode indicates whether sufficient energy is available . basically , it is conceivable to control all steps individually by hand for the removal of a sample , as well as the cocking of the slide , etc ., by activating and deactivating the two gear motors . however , it is expedient to group together the individual steps of the sequence and have them run automatically , with only the following step initiated by activating a switch . this semiautomatic method , as described above , has proven to be especially advantageous . basically , there are two conceivable methods for detecting the actual values and comparing them to the nominal values . one method is based on measuring the lengthwise displacement of the threaded spindle as it is pulled out or pushed in , and measuring the axial displacement of the cutting sheath or the biopsy needle carrier . in order to detect these changes , photocells or miniature switches are arranged inside the housing , in particular on the extension of the base block 8 . in addition , a positioning finger 103 is mounted on the cutting sheath , while the free end 61 protruding from the plunger unit can be used as a measuring point for the threaded spindle of the vacuum pressure - generating device ; if the front edge of the biopsy needle carrier is used as a measuring point with a photocell , no additional positioning finger is required . the embedded photocells are covered with suitable transparent material in case of possible contamination . the positioning finger 103 engages with a slot in the biopsy needle holder . at appropriate places on the extension of the base block 8 there are provided recesses 107 , in which photocells or miniature switches are installed , which interact either with the free end 61 of the plunger spindle , the positioning finger 103 , or an edge of the biopsy needle carrier ( see fig1 ). these signals ( actual value ) are processed in the electronics to form the control signals . the other system is based on measuring the number of revolutions of the dc motors . in this case , a pickup is mounted on the shaft of the dc motor , which interacts with a photocell mounted on the housing of the dc motor . in this way , the number of revolutions of the motor is measured . since the dc motors operate with a speed of around 10 , 000 to 12 , 000 rpm , depending on the load , and on the other hand the secondary planet transmission arranged at the take - off end which interacts with the spindle drive considerably reduces the number of revolutions , an exact lengthwise control is possible . the lengthwise displacement by the spindle drive is a constant value proportional to the operating speed and is therefore sufficient as a control signal for the lengthwise displacement . in order to precisely determine the position of the cutting sheath 3 as well as the plunger 54 at the start , i . e ., after inserting the removable element and closing the housing cover 10 , the dc gear motor 58 rotates the plunger 54 until it strikes against the syringe bottom and the dc gear motor 21 brings the drive of the cutting sheath to a zero position by moving the gear 74 until it strikes against the threaded spindle nut 75 . ( the threaded spindle nut 75 abuts against the gear 74 .) from this zero position , the individual steps are then controlled by comparing the settings and the actual values . the necessary cables from the measuring pickup to the electronics are accommodated in the housing , as is the board with the electronic components . a microprocessor arranged inside the housing , under the cover , with the setpoint values stored in it , controls the individual processes . in order to enable easy insertion of the removable insert unit , the insert aid shown in fig1 and 17 can be used . as fig1 and 17 show in particular , the biopsy needle carrier is enclosed by two brackets 108 and axially fixed in the holder by an additional cross piece 109 , so that it comes to lie parallel to the vacuum / pressure device in the insert aid . the vacuum pressure - generating device is likewise enclosed by the bracket 116 at one side and by the centrally arranged bracket 108 on the other side . in addition , a pin 110 engages with the ventilation borehole 67 . this ensures that the vacuum pressure - generating device is oriented parallel to the biopsy needle carrier ( fig1 ). the parts so oriented are fixed in the insert aid so that they can easily be inserted from above into the hand piece 1 by means of the holder piece 117 . since the parts come in a sterile package with the insert aid , the interchangeable element 20 can be removed from the package without manual contact and be inserted in a sterile manner into the hand piece 1 . the brackets are slightly slanted for easier lodging of the vacuum pressure - generating device and the biopsy needle carrier . since the insert aid is made of plastic , the installed parts can easily be held in place by clamping , thanks to appropriate choice of the tolerance and flexibility . the tip of the needle unit of the biopsy device can be placed directly on the tissue being sampled and inserted into the tissue . it can be expedient , however , to first position a coaxial cannula and then introduce the portion of the needle unit ( consisting of biopsy needle and cutting sheath ) protruding from the hand piece 1 of the biopsy device into the coaxial cannula 125 . in this case , one should make sure that , when the vacuum is created for sucking in the tissue sample , no air can get in from the outside into the space between the inner surface of the coaxial cannula and the outer surface of the needle unit . in the coaxial cannula ( fig1 ) consisting of a tube 121 with cap 122 placed at the proximal end , the tube 121 at the proximal end has a seal element 123 ( e . g ., a properly dimensioned silicone hose ), into which the needle unit is placed . in order to insert the coaxial cannula , a spike 124 is connected to the coaxial cannula 125 . the spike 124 has a tip 126 protruding beyond the distal end of the coaxial cannula in the inserting state . the connection between coaxial cannula and spike is a screw fastening , for example , so that the spike cap is configured as a screw cap 127 . the screw cap is screwed onto the proximal end of the cap 122 . the tube of the coaxial cannula is held in the cap 122 by clamping , for example . after inserting the coaxial cannula , the spike is removed and the needle unit of the biopsy device ( in the cocked condition ) is introduced and positioned in the coaxial cannula ( fig2 ). the distal flank 101 of the guide roller is placed on the proximal end surface 128 of the cap . after the tension slide is released , the needle tip with the sample removal chamber is forced into the tissue to its full length . the depth of penetration of the biopsy needle unit of the biopsy device is between 20 and 35 mm , depending on the selected size of needle . in general , it is 20 mm . in the case of small breasts or tumors lying just below the skin , the depth of penetration of the biopsy needle is therefore too deep , since the biopsy device is placed directly or by means of the guide roller onto the coaxial cannula and the depth of penetration cannot be changed at the device . the depth of penetration is device - fixed . in order to be able to use the same biopsy device with the same biopsy needle and same depth of insertion and the same , i . e ., uniform coaxial cannula with same overall length and less depth of insertion , one or more spacing pieces 129 are placed medially onto the biopsy needle prior to insertion ; thus , these lie medially in front of the guide roller mounted in the housing and the proximal end surface 128 of the cap 122 . thus , by introducing spacing pieces or a spacing piece , the depth of penetration can be changed for the same depth of insertion provided in the device . after inserting the spacing piece , the tip of the biopsy needle in the cocked condition no longer projects slightly from the coaxial cannula , as when no spacing piece is used , but rather lies in the coaxial cannula . the depth of penetration is thus reduced by the length l of the spacing piece ( also see fig2 and 21 ). this does not impair the functioning of the sample removal chamber or the operation of the cutting sheath . for example , if a spacing piece of 10 mm is used with a depth of needle penetration of 20 mm , the depth of penetration will be reduced to 10 mm . of course , the spacing piece can be made up of one or more parts , i . e ., when using spacing pieces of 5 mm thickness , two spacing pieces are necessary to reduce the depth of penetration by 10 mm . the adding of spacing pieces or one spacing piece of corresponding length offers the possibility of using a uniform coaxial cannula including a uniformly added insertion spike 124 for various depths of penetration . the same result regarding a reduced depth of penetration could also be achieved by using caps of different height or by mounting the spacing pieces on the cap , which is equivalent to the threaded - on spacing pieces .
a biopsy device includes a housing . a drive is enclosed in the housing . a biopsy needle assembly has a biopsy needle carrier that carries a biopsy needle . the biopsy needle carrier is positioned in the housing . a vacuum pump is positioned in the housing . the vacuum pump has an elongate cylinder and a piston sealed and movable inside the elongate cylinder . the piston is drivably coupled to the drive . the elongate cylinder is connected to the biopsy needle to generate a vacuum in the biopsy needle when the piston is driven by the drive . the elongate cylinder and the biopsy needle are arranged in parallel by the housing .