DE202010005654U1 - Gas powered surgical instrument - Google Patents

Abstract

A gas-operated surgical instrument (10, 10 ') having a compressed gas connection (44) for connection to a compressed gas source (48), a working piston (68, 68') which can be acted upon by a compressed gas, an actuating element (32) for actuating the instrument (10, 10 ') and a control device (66; 66') coupled to the actuating element (32) and the working piston (68; 68 ') for controlling a feed force of the working piston (68; 68'), characterized in that the control device (66; 66 ') is designed such that it defines a first working area, in which the working piston (68, 68') is movable in the distal direction solely on the basis of a feed force which can be applied with the actuating element (32), for feed forces below a predetermined limit force, and in that Control device (66, 66 ') defines a second operating range above the limit force, in which the working piston (68, 68') is actuated by pressurized gas in the distal direction is movable.

Description

The The present invention relates to a gas powered surgical Instrument with a compressed gas connection for connection to a compressed gas source, a loadable with a pressurized gas working piston, an actuating element for actuating the instrument and one with the actuating element and the working piston coupled control device for controlling a feed force of the working piston.

Instruments of the type described above are for example from the US 2007/0213769 A1 known. They are designed, for example, in the form of pneumatic bone punches or as instruments for locking implants. In order to be able to use the instruments independently of a compressed gas source, with which the instrument is connected via a hose, was in the DE 203 18 275 U1 proposed an instrument in which a filled with a pressurized gas cartridge is available as a source of compressed gas. The disadvantage of using a gas cartridge, however, is that it can provide only a limited volume of gas, whereby an application of the instrument is limited in time or the number of actuation cycles.

It is therefore an object of the present invention, a gas-powered to improve surgical instrument of the type described above, that it with a minimal compressed gas volume a the largest possible number of actuation cycles or allows the longest possible actuation time.

These Task is in a gas-powered surgical instrument The type described above according to the invention thereby solved that the control device is formed is that they have a first work area in which the working piston solely because of a ment with the Betätigungsele applied Feed force is movable in the distal direction, for feed forces defined below a given limit force, and that the Control device a second work area above the limit force defined, in which the working piston by applying pressurized gas is movable in the distal direction.

The proposed development of a gas-operated surgical instrument makes it possible to use as little external gas as possible with compressed gas. Compressed gas is used in the inventively designed control device only in the second or pneumatic work area to move the piston when a certain limit force is exceeded. Below the limit force of the working piston is actuated solely due to a manually initiated feed force. The proposed embodiment of the instrument also has the advantage that the user, despite support in the operation of the instrument with the compressed gas, can work tactile with the instrument. The compressed gas is only used when very high actuating forces must be exerted with the instrument, which is the case for example in bone punches or instruments for locking implants. For actuating paths of the working piston, which are possible with only a small force, namely a force below the limit force, is deliberately omitted in the first or mechanical work area on the support of the compressed gas. In particular, when using compressed gas cartridges so the number of possible total actuation cycles, for example, compared to one of the DE 203 18 275 U1 known instrument, be increased significantly.

Around the tactility of the instrument for a user To improve, it is favorable if the control device is formed such that in the second work area by a Applying pressurized gas to the working piston acting feed force proportional to a coatable with the actuator Feed force is. Even with increasingly required operating force, which is to be exercised by the working piston takes also the force felt by the user. Due to the proportionality the beat by Beauf with compressed gas acting on the working piston Feed force and directly manually with the actuator However, applicable feed force remains tactile for the user in the second workspace above the defined Receive limit force, and stepless. Optionally, it can also be beneficial if the control device is designed such that in the second Work area by applying pressurized gas to the working piston in combination or in cooperation with a support element acting feed force proportional to one with the actuator Applicable feed force is. In particular, the support element in the first working area decoupled from the working piston and relative movable to this, in the second working area with the working piston be axially coupled.

In order to in a simple way the working piston subjected to a pressurized gas can be, it is convenient if the control device comprises a pressurizable gas acted upon working space, which at least partially open towards the working piston is. Thus, the introduced into the working space compressed gas at least acting on a part of the working piston directly and when exceeding one of the limit force associated limit pressure the working piston move.

advantageously, the working piston is displaceably guided in a working cylinder. In this way, a defined movement of the working piston be ensured relative to the instrument.

Around To minimize pressure gas losses, it is advantageous if the working piston and the working cylinder are sealed relative to each other.

Preferably The instrument comprises a support element, which with the Working piston in the first and / or second working area cooperates. Especially can the working piston on the support element in at least support one of the work areas and / or with this be coupled. As a result, in particular, a purely mechanically actuated Work area of one exclusively by compressed gas decouple the working area. Alternatively or in addition can by a coupling of the support member and the working piston in particular change an active surface for the compressed gas, for example, in the coupled state enlarge. As a result, for example, a Vorschubkrafterhöhung be switched on the transition from a first to a second work area of the instrument.

In order to the working piston in a simple way directly by introducing a manual operating force can be moved is it favorable if the working piston in the first working area supported on the support element. For example, can during a movement of the support member in the distal direction of the it also supporting working piston in distal Be moved direction.

Preferably is the working piston in the second working area with the support element coupled. For example, by a coupling of the support element on the working piston an effective surface for the compressed gas be increased, so in the coupled state, for example increases a feed force by appropriate pressurized gas, can be switched on, so to speak. In particular, the working piston be decoupled from the support element in the first work area.

A particularly compact design of the instrument can be achieved be that the working space formed on the support element is. Especially with a movably arranged support element so can the work space "mitwandern", so only the defined on the support element volume of the working space In a first step, pressurized gas must be applied to the working piston away from the support element in the distal direction to move.

manual Actuator forces acting on the actuator can be applied so directly from the support element be transferred to the piston when the Working piston in the first working area directly on the support element supported.

On a compressed gas actuation of the working piston can in particular be waived if the support element in the first Workspace only due to the with the actuator applicable feed force in the distal direction is movable.

For an optimal interaction between the support element and the working piston, it is advantageous if the support element at least partially guided in the working cylinder and when the support member and the working cylinder relative sealed to each other. The support element can so in defined manner, at least partially in the working cylinder and by be guided guided without compressed gas escape can. Optionally or alternatively, it may also be advantageous if the Working piston and the support member relative to each other or slidably guided and sealed against each other are arranged, for example, with a on the working piston and / or on the support element, formed or held sealing element, preferably in shape a sealing ring.

Around to further support a movement of the support element and defined way, it is convenient if the instrument further comprises a guide means for Perform a movement of the support element in distal and proximal direction.

Especially simply the structure of the instrument when the guide device comprises a guide cylinder, in which the support element displaceable is guided. The support element can in particular be formed like a piston in the area in which it is in the guide cylinder slidably guided.

In order to as little compressed gas as possible escape from the instrument can, it is advantageous if the support element and the Guide device are sealed relative to each other.

According to a further preferred embodiment of the invention it can be provided that the control device comprises a locking device for temporary fixing of the support element in the second working area. With the locking device, it is possible, for example, temporarily fix the support member relative to the working cylinder and / or the guide cylinder, so that then the working piston can only be moved in the distal direction by Druckgasbeaufschlagung. Specifying the support element in particular only in the second working range on the instrument, allows only then, when actually high manpower is needed to retrieve the appropriate amount of compressed gas and to use for advancing the working piston.

The Support element can be temporary in a particularly simple manner be determined on the instrument if the locking device is at least a locking member includes for temporarily setting the Supporting element on the guide device or the Working piston. Optionally, it would also be conceivable, the locking device form so that the support element temporarily can be fixed to the working cylinder.

The Construction and manufacture of the instrument can be further simplified if the at least one locking member is formed in the form of a latching and / or clamping element. The clamping element can be particularly effective when the predefined limit force is exceeded is or is. A locking mechanism can also be on simple manner by a latching connection with each other and forming cooperating detent members.

Around the support element in a defined and simple manner on Temporarily set instrument, it is advantageous if the clamping element on the one hand on the support element and on the other supported on the guide device or the working piston. Thus, a direct jamming of the support element means the clamping element on the guide device or on the working piston be achieved, preferably in the second work area.

A particularly simple operation of the locking member can be achieved in that the locking device with a pressurized gas acted upon piston element comprises, which by applying with compressed gas in the distal direction movable and against the at least a locking member can be pressed for jamming the same relative to the support member and relative to the guide means or relative to the working piston. Furthermore, it allows It this particular design, which is used to move the working piston usable compressed gas at the same time for fixing the support element on Instrument, in particular at the guide device or on the working piston to use, depending on the in the instrument prevailing gas pressure. In particular, a deadlock of the at least one locking member relative to the support element and relative to the guide means or relative to the working piston Selbsthemmend done, taking advantage of the recoil principle a Clamping of the cooperating parts is stronger, the stronger the prevailing back pressure.

A defined movement of the piston element on the instrument can in particular be achieved in that the piston element on the support element and / or on the guide device or on the working piston kept guided. So can a defined movement the piston member relative to the support member and relative to the guide device or relative to the working piston be ensured.

to Prevention of further pressure gas losses may also be advantageous be when the piston member and the guide device and / or the working piston are sealed relative to each other. It is also advantageous if the piston element and the support element are sealed relative to each other, here too compressed gas losses to avoid.

conveniently, is the introduced via the actuator Actuating force on a parallel to the working piston movable stored actuator transferable. This allows the actuator due to the initiated actuation force also in the distal direction, that is, towards the working piston, to move, to move it distally.

According to one Another preferred embodiment of the invention be provided that the control device, a pressure regulator includes for controlling a gas pressure acting on the working piston depending on a via the actuator initiable actuating force. The pressure regulator allows in particular, to fix the limit force which the first and separates or defines the second work area. In particular, the pressure regulator may be designed such that the in the instrument in the compressed gas prevailing pressure the working piston only can move above the predefined limit force.

Preferably the pressure regulator is designed to control the on the working piston acting gas pressure as a function of the actuator acting actuating force. Independent of one Design of the actuator is the gas pressure thus only in dependence on the actuator actually acting actuating force regulated.

Of the Construction of the instrument can be further simplified if the Pressure regulator comprises a valve, which in the first working area closed is. Thus, the pressure regulator prevents the working piston in the first working area with pressurized gas with sufficient working pressure can be acted upon for moving the working piston.

Preferably, the pressure regulator comprises a first pressure member for defining an opening force required to open the valve. By the Type and design of the pressure member so the limit force can be preset directly, which must be exceeded in order to open the valve.

A particularly compact arrangement and design of the control device can be achieved in particular by the fact that the first pressure member on the one hand on the pressure regulator and on the other hand on the support element or supported on the working piston. That way that can first pressure element directly on the pressure regulator, optionally also on the pressure regulator Act on valve.

Around the pressure regulator in response to a position of the support element to position on the instrument, it is convenient when the pressure regulator comprises a pressure regulator piston element, which slidably guided in the guide device is.

to Avoiding pressure gas losses, it is advantageous if the pressure regulator piston element and the guide device sealed relative to each other are.

conveniently, the control device comprises a second pressure member for transmission an actuating force from the actuator the pressure regulator. The second pressure member can in particular depending be an acting on it actuation force deformable and for transmitting the initiated operating force be used by the actuator to the pressure regulator.

Further It may be beneficial if the control device a third pressure member comprises, for transmitting an actuating force from the actuator to the pressure regulator. So can two different force ranges through the second and the third Compression element can be defined independently. at the third pressure member may in particular be another Pressure member act. The presence of the second one defined above Pressure element is not mandatory, but optional. Furthermore, the third pressure member also be arranged and designed such that with it an actuating force directly on one of the pressure regulator Covered ventilation valve is transferable.

Around To be able to remove compressed gas from the working space, it is advantageous if the control device is a ventilation valve includes for venting the work space.

In order to the instrument can be made even more compact, it is advantageous if the pressure regulator includes the vent valve.

The Pressure from which the vent valve opens, can You can easily adjust by the fact that the vent valve against the action of the third pressure member is apparent. With the third pressure member can thus directly an opening force be defined to open the vent valve.

Around the size of the instrument as compact as possible Preferably, the pressure regulator piston member comprises the Ventilation valve or part of it.

Of the Working space can be flooded in a defined manner with compressed gas, when the first, the second and the third pressure member are arranged such that a force exerted by the first pressure member force from the second and third pressure member applied forces counteracts. To arrange the pressure members so allows it, an actuating force on the second and initiate third pressure member, in which case if by the second and third pressure member applied force slightly larger is as opposed to the first pressure member acting force, the Valve can be opened to allow the pressurized gas to flow in in the workroom.

Around in the first working area the working piston without applying To be able to move compressed gas, it is favorable if the first, the second and the third pressure member are formed in such a way are that a force exerted by the first pressure member in the first Workspace is always greater than the sum of Forces exerted by the second and third pressure member. It is thus prevented in particular that the valve for manufacturing a fluid connection between the working space and the compressed gas source can be opened.

According to one Another preferred embodiment of the invention a restoring device may be provided for transferring the instrument of a working position, in which the working piston moved in the distal direction, back to a normal position, in which the working piston assumes its most proximal position. If an operator puts the instrument out of his hand, it is possible to automatically bring that instrument back to its basic position. In particular, the restoring device in the form of a be formed pneumatic return device, according to which It can be provided that the working piston by appropriate Exposure to positive or negative pressure in the basic position is moved back.

The structure of the return device is particularly simple if it comprises at least one return member, which is supported on the one hand on the guide means and on the other hand on the working piston and / or on the support member for exerting a force acting in the proximal direction force on the working piston and / or the support member. In particular, it can be supported distally on the working cylinder and on the proximal side on the working piston, so that by the return member acting in the proximal direction restoring force is exerted on the working piston when it has been moved from its most proximal position in the distal direction. Optionally it may, in particular also alternatively, be supported on the working cylinder on the distal side and on the support element on the proximal side so that a restoring force acting in the proximal direction can be exerted on the support element by the restoring member, if this has been moved from its most proximal position in the distal direction.

Preferably the instrument comprises a housing, on or in the Housing the compressed gas connection and / or the working piston and / or the actuating element and / or the regulating device arranged or formed. In particular, the mentioned Components of the instrument protected or at least partially arranged protected in the housing.

to Improving the handling of the instrument, it is advantageous if the housing comprises a grip area and if that Actuator arranged or formed on the handle area or stored. An operator can thus use the instrument on the grip area capture and simultaneously with the same hand the actuator serve.

Preferably the grip area has a compressed gas container receptacle for a compressed gas tank and is the compressed gas connection in the area of or in or at the compressed gas tank receptacle arranged or formed. This allows the compressed gas tank compact and ergonomically optimized to arrange the instrument. In particular, can the compressed gas container receptacle be closed, so that the compressed gas tank completely protected can be arranged on the instrument.

The In particular, surgical instrument, as described above, can be used also be designed in the form of an instrument handle. To be with the Instrument surgical procedures, it is advantageous if at a distal end of the working piston a surgical tool element is arranged.

Around For example, edit tissue or bone with the instrument it is convenient if the surgical Tool element is designed in the form of a cutting edge.

In order to The instrument can be reused, even if the surgical Tool element has been damaged and no longer repaired can be, it is advantageous if the tool element with detachably connectable to the working piston or temporarily can be coupled. It can then depending on the purpose or if needed after wear of the tool element, the optimally suitable tool element be coupled with the working piston.

in principle It would be possible to use the surgical instrument over a compressed gas connection with a compressed gas source, for example to connect to a compressed gas supply system in a hospital. To the instrument independently and in particular hose-disconnected to be able to use, so without disturbing connecting hoses which connect the instrument to the compressed gas source, it is convenient when the compressed gas source filled with a compressed gas Gas tank is and if the gas tank with the Pressure gas connection is detachably connectable. This allows if necessary, the empty gas container from the instrument remove and replace with a full gas container.

preferably, the instrument comprises a compressed gas source in the form of a pressurized gas container. It is then, provided that the compressed gas container is with the Compressed gas filled, an instantly ready to use instrument available, which in the first work area without compressed gas support and in the second work area with compressed gas support can move the working piston in the distal direction.

Preferably, the instrument is in the form of a bone punch. Bone punches often require very high forces, for example of the order of 750 Newton, to machine or cut through bone or tissue, for example. Bone punches have two cooperating tool members, namely an anvil member and a blade that can be moved relative to the anvil member. Typically, the anvil member is connected to the housing of the instrument, the cutting edge preferably detachably connectable to the working piston of the instrument to be able to replace it if necessary. In particular, in bone punching a maximum displacement is given by the structure of the instrument. It corresponds to a distance of the cutting edge from the anvil part in the basic position. If there is no tissue between the cutting edge and the anvil member, no great force is needed to move the cutting blade toward and against the anvil member. In this case, pressurized gas is not required. However, if there is tissue or bone between the cutting edge and the anvil member, then a large amount of labor is needed if the cutting edge and anvil member are to clamp and sever the bone or tissue between them. Only then pressure gas is used by the special design of the instrument to apply the labor required for processing the bone or tissue. Thus, by the control device, a compressed gas consumption can be minimized because of the displacement of the factory generating elements, in which this must exert no force, can be dispensed with a pressurized gas loading of the working piston.

According to one alternative preferred embodiment of the invention The instrument may be in the form of an implant locking instrument be educated. Similar to a bone punch even with a Implantverriegelungsinstrument only on a relative short path or stroke range of the working piston actually a high workforce required to be exercised must, for example, to move implant parts relative to each other, in particular to spread. Only in the second work area will then actually Compressed gas used to power the working piston with the required force to apply that over a manual power manual the actuator is difficult or impossible would.

The following description of preferred embodiments The invention is in connection with the drawing of the closer Explanation. Show it:

1 : An overall schematic view of a gas-powered surgical instrument in the form of a bone punch;

2 a sectional view taken along line 2-2 in FIG 1 ;

3 : An enlarged view of the pressure control device comprehensive part of the instrument in the basic or initial position;

3a : an enlarged view of area A off 3 ;

3b : an enlarged view of area B off 3 ;

3c : an enlarged view of area C off 3 ;

4 : a view analog 3 in the first workspace of the instrument;

4a : an enlarged view of the area D in 4 ;

5 : a view analog 3 still in the first working range of the instrument with increasing pressure gas pressure in the working space;

5a : an enlarged view of the area E in 5 ;

6 : a view analog 3 with exclusive movement of the working piston by Druckgasbeaufschlagung in the second working area;

6a : an enlarged view of the area F in 6 ;

7 an enlarged view of the control device of the instrument when venting the working space;

8a : an enlarged view of the pressure control device comprising part of an alternative embodiment of the instrument in the basic or initial position; and

8b : a view accordingly 8a with exclusive movement of the working piston by Druckgasbeaufschlagung in the second working area.

In 1 schematically a surgical instrument is shown and in total by the reference numeral 10 Mistake. It is designed in the form of a bone punch and includes a handle 12 and one with the handle 12 connected, optionally detachable connectable, shaft part 14 with a relative to the handle 12 fixed or rotationally fixed to this fixable shaft 16 , at its distal end 18 an anvil part 20 in the form of a substantially transverse to one of the shaft 16 defined longitudinal axis 22 extending the projection is formed, which serves as an abutment for a distal end of a shaft 16 slidably mounted stamped part 24 forming cutting edge 26 forms, which for processing bone and / or tissue against the anvil part 20 can be pressed.

The handle 12 which also without the shaft part 14 may perform the function of a surgical instrument according to the invention, for example as an implant locking instrument to move two implant parts relative to each other, comprises a substantially rotationally symmetrical drive part 28 , which itself with the handle 12 connected shaft part 14 in extension of the longitudinal axis 22 extends. At a proximal end of the drive part 28 stands across from this a grip area 30 from where an actuator 32 in the form of a transverse to the longitudinal axis 22 oriented Schenkachse 34 pivotable lever is pivotally mounted, which by an operator in the direction of the arrow 36 on the grip area 30 can be pivoted.

The grip area 30 forms together with the drive part 28 a housing 38 from, on which, as exclusively schematically in 1 shown, a compressed gas container receptacle for receiving a compressed gas container 42 is trained. The compressed gas tank receptacle 40 is in the grip rich 30 integrated. In it is a compressed gas connection 44 formed, with a corresponding connection piece 46 of a compressed gas source 48 forming compressed gas tank 42 can be brought into engagement and gas-tight connectable. Optionally, it would be possible to use the grip area 30 leaner form, as exemplified in 2 shown, and completely on the compressed gas tank receptacle 40 to renounce. The instrument 10 is also optional with a compressed gas source via a compressed gas hose 50 connectable. This allows the instrument 10 even without the use of a gas cylinder 42 for example, by being connected to a pressurized gas supply, such as is usually present in a hospital.

Centerpiece of the instrument 10 is the driving part 28 , It includes a proximal end to the shaft 16 subsequent working cylinder 52 whose inner diameter is slightly more than twice as large as an inner diameter of the shaft 16 , About a radial from the longitudinal axis 22 protruding flange 54 are the shaft 16 and the working cylinder 52 connected with each other. Proximalseitig joins the working cylinder 52 a guide cylinder 56 which, via another, extending in the radial direction flange 58 with the working cylinder 52 connected is. An inner diameter of the guide cylinder 56 is smaller than an inner diameter of the working cylinder 52 but slightly larger than the inner diameter of the shaft 16 , To the guide cylinder 56 closes on the proximal side, via another flange 60 connected, which is in the radial direction from the longitudinal axis 22 extends away, a bearing cylinder 62 which is on the proximal side with an end wall 64 is closed. The inner diameter of the shaft 16 is about two and a half times the inner diameter of the bearing cylinder 62 , The working cylinder 52 , the guide cylinder 56 and the bearing cylinder 62 form part of the housing 38 and a total with the reference numeral 250 designated guide device. They also serve to accommodate the drive of the instrument 10 and one in total with the reference numeral 66 provided control device.

In the working cylinder 52 held and guided is a working piston 68 which is a piston disc 70 and an integrally formed therewith and extending in the distal direction cylinder portion 72 includes. The outer diameter of the massive cylinder section 72 corresponds to the inner diameter of the shaft 16 , The cylinder section 72 Can be made in one piece with the stamped part 24 be educated. Optionally, the cylinder section 72 also by means of a coupling device, not shown, from the stamped part 24 be releasable to the stamped part 24 to replace if necessary. An outer diameter of the piston disc 70 corresponds to the inner diameter of the working cylinder 52 ,

At a distally facing annular surface 74 the piston disc 70 a resetting member is supported 76 forming coil spring. On the distal side, the return element is supported 76 inside the flange 54 from. The reset element 76 is designed as a pressure member and forms part of a restoring device 78 holding the working piston 68 when no user-initiated or requested actuation forces act on it, moves to its home position, namely in the proximal direction, until it engages a support member 80 as in the 2 and 3 shown, applied. The working piston 68 is thus in the working cylinder 52 and in the shaft 16 , and thus at least partially by the management facility 250 , parallel to the longitudinal axis 22 slidably guided in the distal and proximal directions. In one on one of the longitudinal axis 22 way-facing outer surface trained annular groove 82 the piston disc 70 is a sealing element 84 in the form of an O-ring used to seal the working piston 68 and the working cylinder 52 relative to each other.

The support element 80 is in the form of a piston formed with a distal end of the support member 80 forming piston disc 86 integral with a cylinder section extending in the proximal direction 88 is trained. An outer diameter of the piston disc 86 corresponds to the inner diameter of the working cylinder 52 , An outer diameter of the cylinder portion 88 corresponds to the inner diameter of the guide cylinder 56 , In one on one of the longitudinal axis 22 way-facing outer surface trained annular groove 90 the piston disc 86 is a sealing element 92 used in the form of an O-ring for sealing the support element 80 and the working cylinder 52 relative to each other. From the cylinder section 88 is proximal a short sleeve-shaped cylinder section 94 which is coaxial with the longitudinal axis 22 is aligned. An outer diameter of the cylinder portion 94 is about 1.5 times larger than an inner diameter of the bearing cylinder 62 ,

Coaxial to the longitudinal axis 22 is in the cylinder section 88 a blind hole 96 formed, which is open in the distal direction. The inner diameter of the blind hole 96 corresponds to the outer diameter of the cylinder portion 94 and is thus smaller than the inner diameter of the shaft 16 , A proximal end 100 of the cylinder section 94 is with the blind hole 96 about a coaxial to the longitudinal axis 22 extending bore 102 connected. In a remaining cylinder wall 104 of the cylinder section 94 are several evenly distributed over the circumference of the same and parallel to the longitudinal axis 22 extending holes 106 trained, which is also the end 100 with the blind hole 96 connect.

Into the hole 102 used is a bolt section 108 , which is distal with a distal-facing bottom 110 the blind hole 96 flush. The bolt section 108 is a bit longer than the hole 102 and on the proximal side in one piece with another piston disc 112 connected, the outer diameter of the inner diameter of the guide cylinder 96 equivalent. The piston disc 112 is thus something of the proximal end 100 of the cylinder section 94 spaced. In one on one of the longitudinal axis 22 way-facing outer surface trained annular groove 114 the piston disc 112 is a sealing element 116 used in the form of an O-ring to the piston disc 112 and the guide cylinder 56 seal relative to each other.

Coaxial with the holes 106 are on the piston disc 112 in corresponding number and with the same inner diameter holes 118 provided and aligned with the holes 106 aligned. The bolt section 108 can in the opening 102 be glued. Optionally, the blind hole 96 be provided with an internal thread, the bolt section 108 with a corresponding external thread, so that the pin section 108 and the support element 80 can be screwed together. In any case, the bolt section 108 immovable with the cylinder section 94 connected.

From a proximal end surface 120 the piston disc 112 is a cylindrical valve pin 122 coaxial to the longitudinal axis 22 pointing in the proximal direction. At a proximal end thereof is an annular flange 124 formed, on which a sealing element 126 is held, which is inserted in a distally facing annular groove.

On the cylinder section 94 parallel to the longitudinal axis 22 guided is a clamping piston 128 , He has two annular grooves 130 and 132 on, in the radial direction from the longitudinal axis 22 away or in the radial direction on the longitudinal axis 22 pointing are open. In the ring grooves 130 and 132 used are sealing elements 134 and 136 in the form of O-rings for sealing the clamping piston 128 and the guide cylinder 56 or the clamping piston 128 and the cylinder section 94 relative to each other.

Between a ring surface pointing in the proximal direction 138 of the cylinder section 88 and a distally facing annular surface 140 of the clamping piston 128 are two identical clamping elements 142 in the form of slices 144 arranged. Of course, more than two clamping elements can be provided, which also need not be identical. The disks 144 do not define a plane perpendicular to the longitudinal axis 22 but are relative to the longitudinal axis 22 a little inclined. inner edges 146 the discs 144 in the radial direction on the longitudinal axis 22 point, are arranged something more distal than from the longitudinal axis 22 wayward outer edges 148 the discs 144 , The more distal disc 144 is preferably adjacent to the inner edge 146 on the ring surface 138 on, the proximal disc 144 adjacent to its outer edge 148 on the ring surface 140 ,

The control device 66 further comprises a pressure regulating piston 150 , which is a piston disc 152 includes and one of a pointing in the proximal side surface 154 the piston disc 152 protruding cylinder section 156 , The piston disc 152 has an outer diameter that corresponds to the inner diameter of the guide cylinder 56 equivalent. In one in one of the longitudinal axis 22 way-facing outer surface trained annular groove 158 the piston disc 152 is a sealing element 160 used in the form of an O-ring to the piston disc 152 and the guide cylinder 56 seal relative to each other. The cylinder section 156 has an outer diameter that corresponds to the inner diameter of the bearing cylinder 62 equivalent.

For sealing the cylinder section 156 and the guide cylinder 56 relative to each other is on the guide cylinder 56 in the area of the flange 58 one in the direction of the longitudinal axis 22 open annular groove 162 formed, in which a sealing element 164 is used in the form of an O-ring. Slightly spaced and proximal side of the annular groove 162 is in a bearing cylinder 62 forming ring wall 166 one in the direction of the longitudinal axis 22 extending annular groove-like recess 168 formed, one the cylinder section 156 surrounding annulus 170 Are defined. Proximalseitig the recess 168 and slightly spaced from this is analogous to the annular groove 162 another ring groove 172 formed, in which a sealing element 174 used in the form of another O-ring for sealing the cylinder portion 156 and the bearing cylinder 62 relative to each other proximal side of the annulus 170 , The compressed gas connection 44 , which in the form of a sleeve-shaped neck perpendicular to the longitudinal axis 22 outside of the bearing cylinder 62 is about to drill 176 whose longitudinal axis is perpendicular to the longitudinal axis 22 oriented, with the annulus 170 connected.

The cylinder section 156 is hollow and defines an elongated hollow cylindrical interior 178 which extends from a proximal end wall 180 of the cylinder section 156 to the piston disc 152 extends. A sleeve-shaped remaining wall 182 of the cylinder section 156 is with several over the circumference of the wall 182 distributed holes 184 provided, whose longitudinal axes are the longitudinal axis 22 cut vertically. All boh conclusions 184 are in one plane 186 arranged perpendicular to the longitudinal axis 22 is oriented. The holes 184 are also on the cylinder portion 156 positioned them with the annulus 170 be in fluid communication, even if the end wall 180 at an end face pointing in the distal direction 188 the front wall 64 is applied. The extension, that is, a length of the annulus 170 parallel to the longitudinal axis 122 is chosen so that the holes 184 with the annulus 170 even then be in fluid communication when the cylinder section 156 assumes its most distal position, that is displaced maximally far in the distal direction. So it is possible that regardless of a position of the cylinder section 156 relative to the bearing cylinder 62 Compressed gas from the compressed gas source 48 via the compressed gas connection 44 in the interior 178 can get.

In the piston disc 152 is a flat blind hole pointing in the distal direction 190 educated. A floor 192 the blind hole 190 passes through a coaxial to the longitudinal axis 22 trained hole 194 , whose inner diameter is slightly larger than an outer diameter of the valve pin 122 that the bore 194 interspersed. An inside diameter of the interior 178 is slightly larger than an inside diameter of the hole 194 , An outer diameter of the annular flange 124 is slightly smaller than an inside diameter of the interior 178 , The ring flange 124 can with the side surface 154 be brought into abutment, with a part of the same, namely a pointing in the proximal direction annular surface 196 that the interior 178 the hole 194 surrounding limited. With the sealing element 126 can the ring flange 124 and the piston disc 152 be sealed relative to each other.

A first pressure element 198 in the form of a coil spring is supported distally on the end face 120 and on the proximal side of the floor 192 and pushes the piston disc 152 in the proximal direction against the annular flange 124 , The hole 194 is then closed.

At the piston disc 152 is parallel to the hole 194 but spaced from the latter in the radial direction, another bore 200 provided the ground 192 and the side surface 154 connects with each other. Concentric to the longitudinal axis 22 are in the side surface 154 two annular grooves 202 and 204 formed, which are open facing in the proximal direction. They are arranged such that the annular groove 202 in the radial direction from the longitudinal axis 22 a little further apart than the bore 200 , the ring groove 204 a little closer to the longitudinal axis 22 is arranged as the bore 200 , In the ring grooves 202 and 204 are each sealing elements 206 and 208 used in the form of O-rings, with a cylinder section 156 surrounding valve disc 210 work together to drill the hole 200 gastight to close. The valve disc 200 defines a plane perpendicular to the longitudinal axis 22 ,

On an outside of the cylinder section 156 is a flat narrow ring groove 212 trained, in a distance to the side surface 154 which is a little smaller than an extension of the annulus 170 parallel to the longitudinal axis. In the ring groove 212 used is an outer diameter smaller than an outer diameter of the bearing sleeve 62 is having disc 214 , which has a distally facing annular abutment surface 216 Are defined. The disc 214 can simultaneously serve as a stop to a movement of the cylinder portion 156 in the proximal direction, namely, when the disc 214 on the flange 60 strikes. Between the disc 214 and the side surface 154 is an actuator 218 in the form of a flat disc slidably on the cylinder portion 156 arranged, the inner diameter of the outer diameter of the cylinder portion 156 is adapted and the outer diameter of the inner diameter of the guide cylinder 56 is adjusted. A second pressure element 220 in the form of a coil spring is supported on the proximal side of the actuator 218 and distally on the side surface 154 from. A diameter of the second pressure member 220 is slightly larger than an outer diameter of the valve disc 210 ,

A third pressure element 222 also supports the actuator on the proximal side 218 but at the distal end on the valve disc 210 , A spring constant of the second pressure member 220 is slightly larger than a spring constant of the third pressure member 222 , The second pressure element 220 pushes the actuator 218 against the stop surface 216 , The third pressure element 222 pushes the valve disc 210 against the sealing elements 206 and 208 and thus closes the hole 200 ,

The actuator 32 extends over the pivot axis 34 and defines a lever arm 224 , which fork-shaped and two parallel legs 226 is formed comprehensively. He is arranged so that the thighs 226 the forked lever arm 224 directly on the actuator 218 on its side facing in the proximal direction side surface 228 issue. Will the actuator 32 towards the Griffbe rich 30 around the pivot axis 34 pivoted back, so are the thighs 226 moved in the distal direction, take the actuator 218 with and move it in the distal direction.

The operation of the instrument 10 , In particular, the operation of the control device 66 is explained below with reference to the figures.

In the 1 to 3a is the instrument 10 presented in its basic position. The actuator 32 is unconfirmed. The compressed gas source 48 stands with the interior 178 in fluid communication. The from the compressed gas source 48 provided working pressure of the compressed gas acts on the annular flange 124 and pushes it against the ring surface 196 , A valve 230 which is defined by the hole 194 in connection with the ring flange 124 and the sealing element 126 , takes in the basic position of the instrument 10 a closed position. The compressed gas can not therefore through the hole 194 flow through. The reset element 76 pushes the working piston 68 in the proximal direction. The piston disc 70 lies on the piston disc 86 which up to the flange 58 is moved up. The piston disc 112 firmly with the piston disc 86 is thus forced to also moved in the proximal direction. The first pressure element 198 pushes the piston disc 152 in the proximal direction also against the annular flange 124 , The second pressure element 220 pushes the actuator 218 in the proximal direction against the stop surface 216 and the third pressure member 222 pushes the valve disc 210 against the sealing elements 204 and 206 and closes the hole 200 , The hole 200 in conjunction with the valve disc 210 and the sealing elements 206 and 208 defines a vent valve 230 which only counteracts the action of the third pressure member 222 can be opened. The valve 230 can only counteract the action of the first pressure member 198 be opened.

The from the first pressure member 198 applied force is slightly larger than the sum of the second and third pressure member 220 . 222 exerted forces. Acting the working piston 68 only small forces in the area of the tool elements 234 and 236 defining cutting edge 26 or the anvil part 20 contrary, as a result of a pivoting of the actuating element 32 towards the handle area 30 towards the actuator 218 moved in the distal direction. In this first or mechanical workspace of the instrument 10 a movement of the working piston takes place 68 solely because of the with the actuator 32 Applied feed force in the distal direction. The initiated actuating force is via the second pressure member 220 and the third pressure member 222 on the piston disc 152 transmitted and by means of the first pressure member 198 on the piston disc 112 , Located directly on the piston disc 86 supporting working piston 68 is thus moved without support of compressed gas in the distal direction. The first workspace of the instrument 10 is in the 4 and 4a shown.

If the resistance increases between the tool elements 234 and 236 and the force acting there exceeds the sum of the second pressure member 220 and from the third pressure member 222 applied forces, so are the pressure members 220 and 222 compressed. Also the first pressure element 198 is compressed, which causes the valve 230 opens and pressurized gas from the interior 178 in between the piston discs 112 and 152 defined annulus 238 in which the first pressure member 198 is arranged, can flow. The pressurized gas can flow in until a balance of forces between the sum of the first pressure member again 198 applied force and by the pressurized gas in the annulus 238 distal to the piston disc 152 applied force and the sum of the pressure members 220 and 222 on the other side of the piston disc 152 adjusted forces. By pivoting the actuating element 32 on the grip area 30 Thus, successive pressurized gas will enter the annulus 238 initiated. The working piston 68 but still lies on the support element 80 at.

The annulus 238 stands over the holes 118 and the holes 106 with one from the blind hole 96 defined working space 240 in fluid communication. However, the prevailing gas pressure is also in an annulus 242 between the clamping piston 128 and the piston disc 112 and acts on a pointing in the proximal direction ring surface 244 of the clamping piston 128 ,

From a certain gas pressure in the instrument 10 becomes an overall reference numeral 246 providing locking device activated. It includes the clamping piston 128 and the clamping elements 142 , The piston disc 112 shifts in the direction of the clamping piston 128 towards, and with the support of the pressure prevailing in the pressurized gas, the clamping piston 128 moves in the distal direction and pushes the voltage applied to him outside of the disc 144 in the distal direction, causing the support element 80 and the guide cylinder 56 be clamped against each other. The working piston 68 rests in the manner described on the means of the locking device 246 on the guide cylinder 56 fixed support element 80 which is so from a movement of the actuator 218 is decoupled. In addition, one increases between the support element 80 and the guide cylinder 56 acting clamping force with increasing working pressure.

In a further movement of the actuating element 32 towards the handle area 30 towards the pressure members 220 and 222 further shortened, so that in the work space 240 can increase prevailing pressure to a maximum. This prevailing pressure causes the desired high force between the tool elements 234 and 236 by removing the compressed gas in the working space 240 the working piston 68 in the distal direction presses.

As described, the instrument works 10 below a predetermined limit force, which can be adjusted by appropriate selection of the pressure members 198 . 220 and 222 , in the first or mechanical work area. Only above the limit force is by the control device 66 defines a second or pneumatic working area in which the working piston 68 is moved only by applying pressurized gas in the distal direction. This second workspace is in the 6 and 6a shown.

With the instrument 10 Thus, a desired maximum force can be applied solely by the compressed gas. In particular, when using a gas cylinder 42 To reduce gas consumption to a minimum, the pressurized gas through the control device 66 only switched on at high forces.

A pressure regulator 248 of the instrument is formed by the valve 230 and the three pressure members 198 . 220 and 222 in conjunction with the piston disc 152 , It ensures that a working pressure of the compressed gas is proportional to one on the actuator 32 is a force exerted by an operator. This can be done by the working piston 68 infinitely increase the applied force, providing the user with the greatest possible tactility. As in the second or pneumatic work area caused by a shortening of the pressure members 220 and 222 a defined path of both the actuator 32 as well as the actuator 218 It also improves tactility for the user in the second workspace.

Upon a forward movement of the actuator 218 is the force that is the third pressure member 222 always slightly larger than that on the valve disc 210 acting pressure force, so that the compressed gas can not escape, especially not from the working space 240 ,

Will the force on the actuator 32 reduced by the user and this from the grip area 30 pivoted away, are on the return stroke of the working piston 68 the pressure members 220 and 222 extended so that the third pressure member 222 applied force is no longer sufficient to the bore 200 to close. The pressure in the instrument 10 drops off by the compressed gas via the vent valve 232 escapes until the force of the third pressure element 222 again enough to the bore 200 to close. In this way, the pressure drops in the workspace 240 proportional to the distance traveled by the actuator 218 in the proximal direction, albeit with some return hysteresis.

To the instrument 10 In order to protect against overpressure, an overpressure valve, not shown in the figures, may be provided in addition, that is to say optionally, in particular also in all described preferred embodiments of a surgical instrument which is in fluid communication with the interior 178 stands.

In the 8a and 8b is schematically a versus the surgical instrument 10 partially modified instrument shown in the form of a bone punch and overall with the reference numeral 10 ' Mistake. The following essentially only those elements and components of the instrument 10 ' and its operation as far as they are from those of the instrument 10 differ. It should also be noted that identical parts are designated by the same reference numerals, in similar or functionally similar or corresponding parts of the respective reference numeral, a paint ("'") is readjusted.

Centerpiece of the instrument 10 ' is the driving part 28 ' , which opposite the drive part 28 something is modified. The working cylinder 52 , the guide cylinder 56 and the bearing cylinder 62 form part of the housing 38 and a total with the reference numeral 250 ' designated guide device. They also serve to accommodate the drive of the instrument 10 ' and one in total with the reference numeral 66 ' provided control device, which with respect to the control device 66 something is modified.

In the working cylinder 52 held and guided is a working piston 68 ' , which has a cylinder portion extending distally 72 ' includes. The outer diameter of the massive cylinder section 72 ' corresponds to the inner diameter of the shaft 16 ' , which has the same inner diameter as the guide cylinder 56 having. The cylinder section 72 ' Can be made in one piece with the stamped part 24 be educated. Optionally, the cylinder section 72 ' also by means of a coupling device, not shown, from the stamped part 24 be releasable to the stamped part 24 to replace if necessary. From a proximal end surface 120 ' of the cylinder section 72 ' is a cylindrical valve pin 122 ' coaxial to the longitudinal axis 22 pointing in the proximal direction. The valve pin 122 ' is identical in its design and function identical to the valve pin 122 match.

The cylinder section 72 ' has a parallel to the longitudinal axis 22 extending longitudinal groove 252 ' on which is starting from the end face 120 ' extends in the distal direction and has a length which is slightly smaller than an extension of the working cylinder 52 parallel to the longitudinal axis 22 , This results in the instrument 10 ' Overall, a construction in which the cylinder section 72 ' practically the cylinder section 72 as well as the support element of the instrument 10 replaced.

The instrument 10 ' also includes a locking device 246 ' , which are not in the area of the guide cylinder 56 but the cylinder section 72 ' in the area of the working cylinder 52 is formed surrounding. The locking device 246 ' comprises a support element designed in the form of a piston 80 ' which is a piston disc 86 ' includes. This is coaxial with the longitudinal axis 22 with a hole 102 ' Mistake. An outer diameter of the piston disc 86 ' corresponds to an inner diameter of the working cylinder 52 , In one on one of the longitudinal axis 22 way-facing outer surface trained annular groove 90 ' the piston disc 86 ' is a sealing element 92 ' used in the form of an O-ring for sealing the support element 80 ' and the working cylinder 52 relative to each other.

From the piston disc 86 ' is proximal a short, sleeve-shaped and integrally formed with her cylinder section 94 ' which is coaxial with the longitudinal axis 22 is aligned. An outer diameter of the cylinder portion 94 ' corresponds to the outside diameter of the piston disc 86 ' and defines, together with an outer surface facing away from the longitudinal axis thereof, a common cylindrical surface. At a proximal end 100 ' of the cylinder section 94 ' is in the radial direction on the longitudinal axis 22 pointing out a short ring flange 254 ' from which an annular and distal direction Rich stop surface 256 ' Are defined. The support element 80 ' and the cylinder portion 72 ' thus limit an open in the proximal direction annulus 242 ' ,

On the cylinder section 72 ' parallel to the longitudinal axis 22 guided is a substantially disc-shaped clamping piston 128 ' , He has two annular grooves 130 ' and 132 ' on, coaxial with the longitudinal axis 22 formed cylindrical surfaces of the clamping piston 128 ' in the radial direction from the longitudinal axis 22 away or in the radial direction on the longitudinal axis 22 pointing are open. In the ring grooves 130 ' and 132 ' used are sealing elements 134 ' and 136 ' in the form of O-rings for sealing the clamping piston 128 ' and the working cylinder 52 or the clamping piston 128 ' and the cylinder section 72 ' relative to each other.

Between a pointing in the proximal direction and the annulus 242 ' Distally limiting annular surface 138 ' the piston disc 86 ' and a distally facing annular surface 140 ' of the clamping piston 128 ' are two identical clamping elements 142 ' in the form of slices 144 ' arranged. Of course, more than two clamping elements can be provided, which also need not be identical. The disks 144 ' do not define a plane perpendicular to the longitudinal axis 22 but are relative to the longitudinal axis 22 a little inclined. inner edges 146 ' the discs 144 ' in the radial direction on the longitudinal axis 22 point, are arranged something more distal than from the longitudinal axis 22 wayward outer edges 148 ' the discs 144 ' , The more distal disc 144 ' is preferably adjacent to the inner edge 146 ' on the ring surface 138 ' on, the proximal disc 144 adjacent to its outer edge 148 ' on the ring surface 140 ' , A distance between the stop surface 256 ' and the ring surface 138 ' is chosen so that a pointing in the proximal direction annular surface 244 ' of the clamping piston 128 ' at the stop surface 256 ' is applied. The clamping elements 142 ' hold the clamping piston 128 ' under pretension in contact with the ring flange 254 ' ,

At a distally facing annular surface 74 ' the piston disc 86 ' it is supported by a return member 76 forming coil spring. On the distal side, the return element is supported 76 inside the flange 54 from. The reset element 76 is designed as a pressure member and forms part of the return device 78 holding the working piston 68 ' when no user-initiated or requested actuation forces act on it, moves to its home position, namely in the proximal direction, until it, if the return member 76 has a corresponding length, in extreme cases on the flange 58 is applied. Is the reset element 76 about half as long as the working cylinder 52 , reaches the support element 80 ' the flange 58 Not. This is schematically in 8a shown. Preferably, the return member 76 but a sufficient length, so that the support element 80 ' in the basic position on the flange 58 is applied. The working piston 68 ' is thus in the guide cylinder 56 and in the shaft 16 ' , and thus at least partially by the management facility 250 ' , parallel to the longitudinal axis 22 slidably guided in the distal and proximal directions. Optionally, another, in the 8a and 8b not shown reset member may be provided, which on the one hand inside the flange 54 and on the other hand directly on the working piston 68 ' supported, for example, on a radial direction of the working piston 68 ' protruding annular flange, which in the area between the flange 54 and the ring surface 74 ' arranged or formed.

The control device 66 ' is true except for the above-described differences in construction with the control device 66 essentially, so that the above description in conjunction with the instrument 10 can be referenced.

The operation of the instrument 10 ' , ins special also from the control device 66 deviant operation of the control device 66 ' is explained below with reference to the figures.

In a basic position of the instrument 10 ' is the actuator 32 unconfirmed. The compressed gas source 48 stands with the interior 178 in Fluidver connection. The from the compressed gas source 48 provided working pressure of the compressed gas acts on the annular flange 124 and pushes it against the ring surface 196 , The valve 230 takes in the basic position of the instrument 10 ' a closed position. The compressed gas can not therefore through the hole 194 flow through. The reset element 76 pushes the support element 80 ' in the proximal direction. A position of the support element 80 ' in the normal position is given by a length of the formed as a compression spring return member 76 which gives a maximum distance between the flange 54 and the piston disc 86 ' Are defined. As in 8a represented is the end 100 ' something from the flange 58 spaced. Preferably, the return member 76 however, so long that the end 100 ' rests against the flange. The end 120 ' assumes its most proximal position.

The first pressure element 198 pushes the piston disc 152 in the proximal direction also against the annular flange 124 , The second pressure element 220 pushes the actuator 218 in the proximal direction against the stop surface 216 , The third pressure element 222 pushes the valve disc 210 against the sealing elements 204 and 206 and closes the hole 200 , The hole 200 in conjunction with the valve disc 210 and the sealing elements 206 and 208 defines a vent valve 230 which only counteracts the action of the third pressure member 222 can be opened. The valve 230 can only counteract the action of the first pressure member 198 be opened.

The from the first pressure member 198 applied force is slightly larger than the sum of the second and third pressure member 220 . 222 exerted forces. Acting the working piston 68 ' only small forces in the area of the tool elements 234 and 236 defining cutting edge 26 or the anvil part 20 contrary, as a result of a pivoting of the actuating element 32 towards the handle area 30 towards the actuator 218 moved in the distal direction. In this first or mechanical workspace of the instrument 10 a movement of the working piston takes place 68 ' solely because of the with the actuator 32 Applied feed force in the distal direction. The initiated actuating force is via the second pressure member 220 and the third pressure member 222 on the piston disc 152 transmitted and by means of the first pressure member 198 on the end surface 120 ' of the working piston 68 ' , which is thus moved without support of compressed gas in the distal direction. This is the working piston 68 ' in the distal direction relative to the support element 80 ' shifted, which is held by the return member in the normal position. The first workspace of the instrument 10 ' is in the 8a shown.

If the resistance increases between the tool elements 234 and 236 and the force acting there exceeds the sum of the second pressure member 220 and from the third pressure member 222 applied forces, so are the pressure members 220 and 222 compressed. Also the first pressure element 198 is compressed, which causes the valve 230 opens and pressurized gas from the interior 178 in between the end face 120 ' and the piston discs 152 defined annulus 238 ' in which the first pressure member 198 is arranged, can flow. The pressurized gas can flow in until a balance of forces between the sum of the first pressure member again 198 applied force and by the pressurized gas in the annulus 238 ' distal to the piston disc 152 applied force and the sum of the pressure members 220 and 222 on the other side of the piston disc 152 adjusted forces. By pivoting the actuating element 32 on the grip area 30 Thus, successive pressurized gas will enter the annulus 238 ' introduced, which in particular directly on the end face 120 ' of the working piston 68 ' acts. The end 100 ' is still on the flange 58 at.

The annulus 238 ' stands over the longitudinal groove 252 ' with a cylinder section 72 ' annularly surrounding working space 240 ' in fluid communication. The workroom 240 ' is limited by the flange 58 , the working cylinder 52 , the end 100 ' and the ring surface 244 ' , The prevailing gas pressure thus acts on the ring surface pointing in the proximal direction 244 ' of the clamping piston 128 ' as well as on the end 100 ' ,

From a certain gas pressure in the instrument 10 ' becomes the locking device 246 ' activated. The prevailing gas pressure acts on the end 100 ' as well as the ring area 244 ' and moves the support element 80 ' against the action of the return member 76 in the distal direction. The prevailing gas pressure and that of the restoring member 76 on the support element 80 ' applied force counteract each other. Once the through the compressed gas in the work space 240 ' to the end 100 ' acting force of the increasingly compressed return member 76 corresponds to the applied restoring force, which acts in the working space 240 ' prevailing gas pressure on the proximal side on the clamping piston 128 ' , This presses in the distal direction against the clamping elements 142 ' , The clamping piston 128 ' presses the outside of the disc against it 144 in the distal direction, causing the support element 80 ' and the cylinder portion 72 ' be clamped against each other.

The working piston 68 ' forms in the manner described with the means of the locking device 246 ' at the cylinder section 72 ' fixed support element 80 ' one unity. The one in the instrument 10 ' prevailing gas pressure thus acts not only as described directly on the working piston 68 ' over the end surface 120 ' , but also indirectly via the support element 80 ' one being essentially from the end face 120 ' defined effective area of the working piston 68 ' one from the end 100 ' as well as the end face 244 ' defined, transverse to the longitudinal axis 22 acting in the proximal direction, stepped active surface acts. The relative to the working cylinder 52 sealed support element 80 ' thus forms a part of the working piston above a certain gas pressure 68 ' , By the described effective area enlargement of the working piston 68 ' a feed force acting on it is increased as soon as the action of the locking device 246 ' starts.

In a further movement of the actuating element 32 towards the handle area 30 towards the pressure members 220 and 222 further shortened, so that in the work space 240 ' can increase prevailing pressure to a maximum. This prevailing pressure causes the desired high force between the tool elements 234 and 236 by the pressurized gas in the annulus 238 ' as well as in the workroom 240 ' the working piston 68 ' pushes in the distal direction.

As described, the instrument works 10 ' below a predetermined limit force, which can be adjusted by appropriate selection of the pressure members 198 . 220 and 222 , in the first or mechanical work area. Only above the limit force is by the control device 66 ' defines a second or pneumatic working area in which the working piston 68 ' additionally moved with compressed gas support in the distal direction. This second workspace is schematic in 8b shown. In the second work area becomes the support element 80 ' the working piston 68 ' switched on, so to speak. At the instrument 10 is the support element 80 intermediate and has a clearer separation between mechanical and gas-powered work area result.

Also with the instrument 10 ' Thus, a desired maximum force can be applied substantially solely by the compressed gas. In particular, when using a gas cylinder 42 To reduce gas consumption to a minimum, the pressurized gas through the control device 66 ' only switched on at high forces.

The pressure regulator 248 Ensures that a working pressure of the compressed gas is proportional to one on the actuator 32 is a force exerted by an operator. This can be done by the working piston 68 ' infinitely increase the applied force, providing the user with the greatest possible tactility. As in the second or pneumatic work area caused by a shortening of the pressure members 220 and 222 a defined path of both the actuator 32 as well as the actuator 218 It also improves tactility for the user in the second workspace.

Upon a forward movement of the actuator 218 is the force that is the third pressure member 222 exerts, always slightly larger than the disc on the valve 210 acting pressure force, so that the compressed gas can not escape, especially not from the working space 240 ' ,

Will the force on the actuator 32 reduced by the user and this from the grip area 30 pivoted away, are on the return stroke of the working piston 68 ' the pressure members 220 and 222 extended so that the third pressure member 222 applied force is no longer sufficient to the bore 200 to close. The pressure in the instrument 10 ' drops off by the compressed gas via the vent valve 232 escapes until the force of the third pressure element 222 again enough to the bore 200 to close. In this way, the pressure drops in the workspace 240 ' proportional to the distance traveled by the actuator 218 in the proximal direction, albeit with some return hysteresis.

To the instrument 10 ' In order to protect against overpressure, a pressure relief valve, not shown in the figures, may additionally be provided which is in fluid communication with the interior 178 stands.

In the described instruments 10 and 10 can over most of the working piston 68 respectively 68 ' traveled path, on which no or only a small force between the tool elements 234 and 236 acts, the force applied mechanically by the user. Only on the last part of the way the full work force is applied by Druckgasbeaufschlagung. With conventional jaw widths of bone punches of 20 mm and usual working distances of about 5 mm, so only about a quarter of the possible total travel or stroke of the working piston 68 , only on a quarter of the total stroke is the working piston 68 moved pneumatically in the instrument according to the invention, three quarters of the way purely mechanically. This reduces gas consumption to about a quarter. With the same Chen gas quantity can thus about four times as many operations of the instruments of the invention 10 and 10 ' with maximum manpower than instruments without the control devices 66 respectively 66 ' ,

The variably adjustable pressure regulator 248 thus allows both the instrument 10 as well as the instrument 10 ' a stepless change of working pressure during operation. This ensures maximum tactility. Furthermore, the gas consumption is reduced to a minimum by the described combination of mechanical and pneumatic feed. This can be compared to conventional instruments significantly smaller compressed gas tank 42 be used, which is the case of the housing 38 significantly reduce defined volumes compared to known instruments.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• US 2007/0213769 A1 [0002]
• - DE 20318275 U1 [0002, 0005]

Claims (50)

Gas powered surgical instrument ( 10 ; 10 ' ) with a compressed gas connection ( 44 ) for connection to a compressed gas source ( 48 ), a pressurizable with a pressurized gas piston ( 68 ; 68 ' ), an actuator ( 32 ) for operating the instrument ( 10 ; 10 ' ) and one with the actuator ( 32 ) and the working piston ( 68 ; 68 ' ) coupled control device ( 66 ; 66 ' ) for controlling a feed force of the working piston ( 68 ; 68 ' ), characterized in that the control device ( 66 ; 66 ' ) is designed such that it has a first working area, in which the working piston ( 68 ; 68 ' ) solely due to one with the actuator ( 32 ) can be moved applicably in the distal direction, defined for feed forces below a predetermined limit force, and that the control device ( 66 ; 66 ' ) defines a second operating range above the limit force in which the working piston ( 68 ; 68 ' ) is movable in the distal direction by applying pressurized gas. Surgical instrument according to claim 1, characterized in that the control device ( 66 ; 66 ' ) is designed such that in the second work area by applying a pressurized gas to the working piston ( 68 ; 68 ' ) acting feed force proportional to one with the actuating element ( 32 ) is applicable feed force. Surgical instrument according to claim 1 or 2, characterized in that the control device ( 66 ) a pressurizable gas space ( 240 ), which in the direction of the working piston ( 68 ) is at least partially open. Surgical instrument according to one of the preceding claims, characterized in that the working piston ( 68 ; 68 ' ) in a working cylinder ( 52 ) is guided displaceably. Surgical instrument according to claim 4, characterized in that the working piston ( 68 ; 68 ' ) and the working cylinder ( 52 ) are sealed relative to each other. Surgical instrument according to one of the preceding claims, characterized by a support element ( 80 ; 80 ' ), which with the working piston ( 68 ; 68 ' ) cooperates in the first and / or second work area. Surgical instrument according to claim 6, characterized in that the working piston ( 68 ) is supported in the first working area on the support element. Surgical instrument according to claim 6 or 7, characterized in that the working piston ( 68 ' ) in the second work area with the support element ( 80 ' ) is coupled. Surgical instrument according to one of claims 6 to 8, characterized in that the working space ( 240 ) on the support element ( 80 ) is trained. Surgical instrument according to one of claims 7 to 9, characterized in that the working piston ( 68 ) in the first working area directly on the support element ( 80 ) is supported. Surgical instrument according to one of claims 7 to 10, characterized in that the support element ( 80 ) in the first work area only due to the with the actuator ( 32 ) is applied movable feed force in the distal direction. Surgical instrument according to one of claims 7 to 11, characterized in that the support element ( 80 ; 80 ' ) at least in sections in the working cylinder ( 52 ) and that the support element ( 80 ; 80 ' ) and the working cylinder ( 52 ) are sealed relative to each other. Surgical instrument according to one of Claims 7 to 12, characterized by a guide device ( 250 ; 250 ' ) for guiding a movement of the support element ( 80 ) in the distal and proximal directions. Surgical instrument according to claim 13, characterized in that the guiding device ( 250 ) a guide cylinder ( 56 ), in which the support element ( 80 ) is guided displaceably. Surgical instrument according to claim 13 or 14, characterized in that the support element ( 80 ; 80 ' ) and the management body ( 250 ; 250 ' ) are sealed relative to each other. Surgical instrument according to one of claims 7 to 15, characterized in that the regulating device ( 66 ; 66 ' ) a locking device ( 246 ; 246 ' ) for temporarily fixing the support element ( 80 ; 80 ' ) in the second workspace. Surgical instrument according to claim 16, characterized in that the locking device ( 246 ; 246 ' ) at least one locking member ( 142 ; 142 ' ) for temporarily fixing the support element ( 80 ; 80 ' ) at the management facility ( 250 ) or the working piston ( 68 ' ). Surgical instrument according to claim 16, characterized in that the at least one locking member ( 142 ; 142 ' ) in the form of a latching and / or clamping element ( 144 ; 144 ' ) is trained. Surgical instrument according to claim 18, characterized in that the clamping element ( 144 ; 144 ' ) on the one hand on the support element ( 80 ; 80 ' ) and on the other hand at the management facility ( 250 ) or on the working piston ( 68 ' ) is supported. Surgical instrument according to one of claims 16 to 19, characterized in that the locking device ( 246 ; 246 ' ) a pressurizable gas piston element ( 128 ; 128 ' ), which is movable in the distal direction by applying compressed gas and against the at least one locking member ( 142 ; 142 ' ) can be pressed for clamping the same relative to the support element ( 80 ' ) and relative to the lead institution ( 250 ) or relative to the working piston ( 68 ' ). Surgical instrument according to claim 20, characterized in that the piston element ( 128 ; 128 ' ) on the support element ( 80 ; 80 ' ) and / or at the management facility ( 250 ) or on the working piston ( 68 ' ) is kept guided. Surgical instrument according to claim 20 or 21, characterized in that the piston element ( 128 ; 128 ' ) and the management body ( 250 ) and / or the working piston ( 68 ' ) are sealed relative to each other. Surgical instrument according to one of the preceding claims, characterized in that via the actuating element ( 32 ) introduced actuating force on a parallel to the working piston ( 68 ; 68 ' ) movably mounted actuator ( 218 ) is transferable. Surgical instrument according to one of the preceding claims, characterized in that the regulating device ( 66 ; 66 ' ) a pressure regulator ( 248 ) comprises for regulating one on the working piston ( 68 ; 68 ' ) acting gas pressure as a function of a via the actuating element ( 32 ) initiable operating force. Surgical instrument according to claim 24, characterized in that the pressure regulator ( 248 ) is adapted for controlling the on the working piston ( 68 ; 68 ' ) acting gas pressure in dependence on the actuator ( 218 ) acting actuating force. Surgical instrument according to claim 24 or 25, characterized in that the pressure regulator ( 248 ) a valve ( 230 ), which is closed in the first work area. Surgical instrument according to one of claims 24 to 26, characterized in that the pressure regulator ( 248 ) a first pressure member ( 198 ) for defining one for opening the valve ( 230 ) required opening force. Surgical instrument according to claim 27, characterized in that the first pressure member ( 198 ) on the pressure regulator ( 248 ) and on the other hand on the support element ( 80 ) or on the working piston ( 68 ' ) is supported. Surgical instrument according to one of claims 24 to 28, characterized in that the pressure regulator ( 248 ) a pressure regulator piston element ( 150 ), which in the guide device ( 250 ; 250 ' ) is guided displaceably. Surgical instrument according to claim 29, characterized in that the pressure regulator piston element ( 150 ) and the management body ( 250 ; 250 ' ) are sealed relative to each other. Surgical instrument according to one of claims 23 to 30, characterized in that the control device ( 66 ; 66 ' ) a second pressure member ( 220 ) for transmitting an actuating force from the actuator (10) 218 ) on the pressure regulator ( 248 ). Surgical instrument according to one of claims 23 to 31, characterized in that the control device ( 66 ; 66 ' ) a third pressure member ( 222 ) for transmitting an actuating force from the actuator (10) 218 ) on the pressure regulator ( 248 ). Surgical instrument according to one of claims 3 to 32, characterized in that the control device ( 66 ; 66 ' ) a ventilation valve ( 232 ) for ventilating the working space ( 240 ). Surgical instrument according to claim 33, characterized in that the pressure regulator ( 248 ) the ventilation valve ( 232 ). Surgical instrument according to claim 33 or 34, characterized in that the ventilation valve ( 232 ) against the action of the third pressure member ( 222 ) is openable. Surgical instrument according to one of Claims 33 to 35, characterized in that the pressure regulator piston element ( 150 ) the ventilation valve ( 232 ) or a part thereof. Surgical instrument according to one of claims 32 to 36, characterized in that the first, the second and the third pressure member ( 198 . 220 . 222 ) are arranged such that one of the first pressure member ( 198 ) applied force from the second and third pressure member ( 220 . 222 ) counteracts applied forces. Surgical instrument according to one of claims 32 to 37, characterized in that the first, the second and the third pressure member ( 198 . 220 . 222 ) are formed such that one of the first pressure member ( 198 ) applied force in the first work area is always greater than the sum of the second and third pressure member ( 220 . 222 ) exerted forces. Surgical instrument according to one of the preceding claims, characterized by a restoring device ( 78 ) for transferring the instrument ( 10 ; 10 ' ) of a working position, in which the working piston ( 68 ; 68 ' ) is moved in the distal direction, in a normal position, in which the working piston ( 68 ; 68 ) assumes its most proximal position. Surgical instrument according to claim 39, characterized in that the restoring device ( 78 ) at least one reset member ( 76 ), which on the one hand at the guide device ( 250 ; 250 ' ) and on the other hand on the working piston ( 68 ) and / or on the support element ( 80 ' ) for exerting a force acting in the proximal direction on the working piston ( 68 ; 68 ' ) and / or the support element ( 80 ' ). Surgical instrument according to one of the preceding claims, characterized by a housing ( 38 ) and that on or in the housing ( 38 ) the compressed gas connection ( 44 ) and / or the working piston ( 68 ; 68 ' ) and / or the actuating element ( 32 ) and / or the control device ( 66 ; 66 ' ) are arranged or formed. Surgical instrument according to claim 41, characterized in that the housing ( 38 ) a grip area ( 30 ) and that the actuating element ( 32 ) on the grip area ( 30 ) is arranged or formed or stored. Surgical instrument according to claim 42, characterized in that the grip area ( 30 ) a compressed gas container receptacle ( 40 ) for a pressurized gas container ( 42 ) and that the compressed gas connection ( 44 ) in the region of or in or on the compressed gas container receptacle ( 40 ) is arranged or formed. Surgical instrument according to one of the preceding claims, characterized in that at a distal end of the working piston ( 68 ; 68 ' ) a surgical tool element ( 234 ) is arranged. Surgical instrument according to claim 44, characterized in that the surgical tool element ( 234 ) in the form of a cutting edge ( 26 ) is trained. Surgical instrument according to claim 44 or 45, characterized in that the tool element ( 234 ) with the working piston ( 68 ; 68 ' ) is releasably connectable or temporarily coupled. Surgical instrument according to one of the preceding claims, characterized in that the compressed gas source ( 48 ) a filled with a compressed gas gas container ( 42 ) and that the gas container ( 42 ) with the compressed gas connection ( 44 ) is releasably connectable. Surgical instrument according to one of the preceding claims, characterized by a compressed gas source ( 48 ) in the form of a compressed gas container ( 42 ). Surgical instrument according to one of the preceding claims, characterized in that the instrument ( 10 ; 10 ' ) is formed in the form of a bone punch. Surgical instrument according to one of claims 1 to 45, characterized in that the instrument ( 10 ; 10 ' ) is formed in the form of an implant locking instrument.