US20050199407A1

US20050199407A1 - Surgical instrument

Info

Publication number: US20050199407A1
Application number: US11/062,314
Authority: US
Inventors: Reiner Hermann
Original assignee: Aesculap AG
Current assignee: Aesculap AG
Priority date: 2002-09-04
Filing date: 2005-02-17
Publication date: 2005-09-15

Abstract

In a surgical instrument comprising a tool which is oscillatingly pivotable about an axis of rotation and a rotatingly driven drive shaft which by means of an eccentric causes an oscillating lever which is rotationally fixedly connected to the tool to pivot oscillatingly back and forth, in order to achieve a simplified adaptation of the pivoting angle to the respective tool, it is proposed that the drive shaft comprise adjacent to each other at least two eccentrics with different eccentricity, that an oscillating lever pivotable about the axis of rotation of the tool be associated with each eccentric, and that the tool be rotationally fixedly connected to only one of the oscillating levers.

Description

This application is a continuation of International Application No. PCT/EP2003/009664 filed on Aug. 30, 2003.
The present disclosure relates to the subject matter disclosed in International Application No. PCT/EP2003/009664 of Aug. 30, 2003 and German Application No. 102 40 655.3 of Sep. 4, 2002, which are incorporated herein by reference in their entirety and for all purposes.

BACKGROUND OF THE INVENTION

The invention relates to a surgical instrument comprising a tool which is oscillatingly pivotable about an axis of rotation and a rotatingly driven drive shaft which by means of an eccentric causes an oscillating lever which is rotationally fixedly connected to the tool to pivot oscillatingly back and forth.
Such surgical instruments are used, for example, for saw blades, trephines, oscillating drills or similar tools. The angle of the oscillating rotary movement of the tools depends on the type of tool. Relatively large pivoting angles are often required for instruments with a small radius. Tools with a large radius, on the other hand, for example, trephines require relatively small pivoting angles.
With conventional instruments, these different pivoting angles are obtained by use of different handpieces or drive components which make a certain pivoting angle available. There are also handpieces which enable adjustment of the pivoting angle, but a complicated adjusting mechanism, which involves a very complex setup, is required for this.
In all cases there is the danger that owing to selection of a wrong handpiece or owing to wrong adjustment, the user will select a pivoting angle which is unsuitable for the respective tool.
The object of the invention is to so construct a generic instrument that with simple means it is ensured that a tool can be operated with the pivoting angle required for this tool.

SUMMARY OF THE INVENTION

This object is accomplished, in accordance with the invention, with a surgical instrument of the kind described at the outset in that the drive shaft comprises at least two eccentrics with different eccentricity adjacent to each other, in that an oscillating lever pivotable about the axis of rotation of the tool is associated with each eccentric, and in that the tool is rotationally fixedly connected to only one of the oscillating levers.
The surgical instrument thus makes at least two oscillating levers available, which are made to pivot oscillatingly with a different pivoting angle by the drive shaft, and the tool is rotationally fixedly connected by suitable means to only one of these oscillating levers respectively, so that the pivoting angle attainable for this tool corresponds to that of the corresponding oscillating lever.
In this way, it is, for example, possible, when manufacturing such a surgical instrument, to use a universal instrument, into which different tools are selectively insertable. The pivoting angle required for the inserted tool is then determined directly by the manufacturer by rotationally fixed connection of this tool with only one of the two oscillating levers.
With this construction, a possibility is, however, particularly advantageous, wherein in a single surgical instrument different tools are rotationally fixedly connected to different oscillating levers. Different tools which have to be operated with different pivoting angles thus belong to the surgical instrument, and these are designed so as to establish a rotationally fixed connection only with that oscillating lever in the instrument which provides the proper pivoting angle for the respective tool. With a single drive shaft, it is thus possible in a very simple way, without any adjustment, to provide different pivoting angles for the different tools.
It is particularly advantageous for the tool in a working position to be releasably connected to one oscillating lever and to be pullable out of this working position out of the instrument. Easy exchange of the tool is thus possible. Upon inserting the tool, this automatically connects with that oscillating lever which provides the correct pivoting angle for this tool. Operating errors are excluded, and tools with a different pivoting angle can be operated with one drive shaft.
It is advantageous for the tool to be securable against axial displacement in the pushed-in operating position in the instrument, so that the rotationally fixed connection with a certain oscillating lever is thereby ensured.
Provision is made in a particularly preferred embodiment for the rotationally fixed connection to be formed by radial recesses and projections which enter into and rest against these recesses in circumferential direction interlocking with one another and allowing axial displacement of the tool relative to the drive shaft. The rotationally fixed connection can thus be established and released simply by axial displacement of the projections and recesses relative to one another, and this relative displacement is brought about by inserting a tool into the instrument.
It is advantageous for the projection to be formed by an axially parallel, radially protruding rib.
The recess is preferably formed by an axially parallel groove.
Provision is made in a particularly preferred embodiment for each oscillating lever to carry a recess and for each tool to have only one projection which is arranged in axial direction along the tool so as to establish a rotational connection with only one oscillating lever. When the user inserts the tool into the instrument, this projection is thus automatically located opposite one of the grooves of the oscillating levers and establishes a rotationally fixed connection with this oscillating lever, but not with any other oscillating levers.
It is advantageous for the eccentrics to be arranged in a different angular position. A balancing of the drive shaft can thereby be effected, and particularly smooth running of the instrument is thus obtained. In particular, it is advantageous, in the case of two eccentrics, for these to be offset in opposite direction.
The following description of preferred embodiments of the invention serves in conjunction with the drawings to explain the invention in greater detail.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a longitudinal sectional view through a surgical instrument with two adjacently arranged oscillating levers and a tool coupling with the rear oscillating lever;
FIG. 2 shows a view similar to FIG. 1 with another tool coupling only with the front oscillating lever; and
FIG. 3 shows a sectional view taken on line 3-3 in FIG. 2.

DETAILED DESCRIPTION OF THE INVENTION

The surgical instrument 1 depicted in the drawings comprises a housing 2, in which there is mounted in ball bearings 3, 4 a drive shaft 5 which carries a drive pinion 6 at one end thereof. The drive pinion 6 meshes with a pinion 7 on a connecting shaft 8, which is likewise mounted by means of ball bearings 9 in the housing 2 and is surrounded by a connection piece 10 by means of which the housing 2 can be connected to a flexible drive shaft 11. The drive shaft 11 comprises a casing 12 and a rotatable shaft 13 therein, which is rotated by an external drive, not depicted in the drawings, and which can be rotationally fixedly coupled with the connecting shaft 8. In this way, the drive shaft 5 can be made to rotate continuously.
A receiving bore 14 for the shaft 15 of a tool 16 is arranged parallel and adjacent to the drive shaft 5 in the housing 2. This receiving bore 14 is open towards the side of the housing 2 facing away from the connection piece 10, so that the shaft 15 of the tool 16 can be inserted into the receiving bore 14 from this open side. Inserted in the receiving bore 14 is a bearing sleeve 17 which is freely rotatable in the receiving bore 14 and is secured in axial direction in the receiving bore 14 by a transverse pin 18.
A quick coupling 19 engages over the receiving bore 14 at the open end thereof. When the tool 16 is inserted, a locking member 20 of the quick coupling 19 engages in a circumferential groove 21 of the tool 16 and thereby fixes the tool in axial direction in the bearing sleeve 17 and thus in the receiving bore 14. The locking members 20 can be released in a manner known per se and not described herein in more detail by a grip sleeve 22 being pressed against the action of a spring 23, so that the tool 16 can then be pulled in axial direction out of the bearing sleeve 17 and thus out of the receiving bore 14.
The tool 16 may differ in design. In the embodiment shown, a trephine with a small diameter is depicted in FIG. 1 and a trephine with a larger diameter in FIG. 2.
Two oscillating levers 25, 26 are rotatably mounted side by side on the bearing sleeve 17 and are separated by a spacer ring 24. These oscillating levers comprise a circular bearing ring 27 surrounding the bearing sleeve 17, and two parallel webs 29 forming between them an engagement opening 28 which is open at one side thereof. The webs 29 extend on either side of the drive shaft 5. The drive shaft 5 comprises an eccentric section 30 and 31, respectively, in the region of the oscillating levers 25 and 26. The eccentricity of these eccentric sections 30 and 31 is different. The eccentric sections 30 and 31 are offset from each other in circumferential direction through approximately 180°. Each eccentric section 30, 31 carries a ball bearing 32 and 33, respectively.
These ball bearings 32 and 33 engage in the engagement openings 28 of the two oscillating levers 25 and 26 with a tight fit, so that upon rotation of the drive shaft 5, both oscillating levers 25, 26 are pivoted oscillatingly to and fro, more particularly, in accordance with the different eccentricity of the eccentric sections 30 and 31 with different maximum pivoting angle.
An axially parallel groove 34, 35 is arranged in each of the two oscillating levers 25, 26 on the inner side of the bearing ring 27. These two grooves 34 and 35 are oriented in alignment with each other.
An axially parallel slot 38 is arranged in the bearing sleeve 17 in a rear section 36 which dips into the bearing rings 27 and has a smaller diameter than the front section 37 of the bearing sleeve 17. The slot 38 narrows in the direction of insertion of the tool 16 and extends beyond the two oscillating levers 25 and 26.
The tool 16 carries on its shaft 15 a radially protruding catch 39. When the shaft 15 is pushed into the bearing sleeve 17, the catch 39 enters the slot 38 and a certain guidance is imparted to it therein. When the shaft 15 is pushed in completely, the catch 39 enters groove 34 or groove 35 of the two oscillating levers 25, 26. Which of the two grooves 34, 35 the catch 39 enters will depend on the axial position of the catch 39 on the shaft 15. In the embodiment of FIG. 1 the catch 39 is arranged such that when the shaft 15 is pushed in completely, the catch 39 engages the groove 35 of the rear oscillating lever 26. In the embodiment of FIG. 2, on the other hand, the catch 39 is arranged more towards the front end of the tools and therefore enters groove 34 of the oscillating lever 25. The catch 39 thus makes a rotationally fixed connection between the tool 16 and one of the two oscillating levers 25, 26. This rotationally fixed connection also includes the bearing sleeve 17 as the catch 39 passes through the slot 38. In accordance with the respective pivoting angle of the oscillating lever 25, 26 with which this rotationally fixed connection has been made, the tool will then be made to pivot oscillatingly with a different pivoting angle.
Selection of the correct oscillating lever results automatically from the position of the catch on the tool. The user only has to push the respective tool into the housing 2 and secure it in axial direction by means of the quick coupling 19. A connection with the “correct” oscillating lever is then made automatically, and the tool is driven with that pivoting angle which is suitable for this tool.
Only two such oscillating levers 25, 26 are provided in the embodiment shown. It is, in principle, also possible for more oscillating levers to be arranged adjacent to one another, each having an eccentric section with a different eccentricity associated therewith and thus a different pivoting angle. By means of different positioning, the catch 39 on the tools could then selectively choose the pivoting appropriate for the respective tool. This results in a construction which is very easy for the user to handle. When he pushes a certain tool into the housing 2, the rotational coupling with the correct oscillating lever occurs automatically. The possibility of making a mistake is dispensed with. The tool itself will select the appropriate oscillating lever therefor.

Claims

1. Surgical instrument comprising a tool which is oscillatingly pivotable about an axis of rotation and a rotatingly driven drive shaft which by means of an eccentric causes an oscillating lever which is rotationally fixedly connected to the tool to pivot oscillatingly back and forth, wherein the drive shaft comprises at least two eccentrics with different eccentricity adjacent to each other, an oscillating lever pivotable about the axis of rotation of the tool is associated with each eccentric, and the tool is rotationally fixedly connected to only one of the two oscillating levers.

2. Instrument in accordance with claim 1, wherein different tools are rotationally fixedly connected to different oscillating levers.

3. Instrument in accordance with claim 1, wherein the tool in a working position is releasably connected to one oscillating lever and is pullable out of this working position out of the instrument.

4. Instrument in accordance with claim 3, wherein the tool is securable in the pushed-in working position against axial displacement in the instrument.

5. Instrument in accordance with claim 1, wherein the rotationally fixed connection is formed by radial recesses and projections which enter into and rest against these recesses in circumferential direction interlocking with one another and allowing axial displacement of the tool relative to the drive shaft.

6. Instrument in accordance with claim 2, wherein the rotationally fixed connection is formed by radial recesses and projections which enter into and rest against these recesses in circumferential direction interlocking with one another and allowing axial displacement of the tool relative to the drive shaft.

7. Instrument in accordance with claim 5, wherein the projection is formed by an axially parallel, radially protruding rib.

8. Instrument in accordance with claim 5, wherein the recess is formed by an axially parallel groove.

9. Instrument in accordance with claim 6, wherein the recess is formed by an axially parallel groove.

10. Instrument in accordance with claim 8, wherein each oscillating lever carries a recess, and each tool has only one projection which is arranged in axial direction along the tool so as to form a rotational connection with only one oscillating lever.

11. Instrument in accordance with claim 5, wherein the angular position of the projections and recesses, respectively, on the oscillating levers is the same.

12. Instrument in accordance with claim 11, wherein guides which narrow in the direction of insertion of the tool are provided to rotate the tool such that the projections and recesses are oriented in alignment with one another.

13. Instrument in accordance with claim 12, wherein the guides are formed by a narrowing longitudinal groove in a bearing sleeve surrounding the tool.

14. Instrument in accordance with claim 1, wherein the eccentrics are arranged in a different angular position.

15. Instrument in accordance with claim 14, wherein in the case of two eccentrics, these are offset in opposite direction.