STERILE UNIT AND MANIPULATOR FOR ROBOTIC SURGERY

Abstract

A sterile unit for the sterile connection of an instrument drive unit to a surgical instrument, including: a base with a circular passageway orifice having a transmission element supported to be rotatable around a rotational axis and axially movable in a direction of the rotational axis in a movement range between first and second end positions. The sterile unit also includes a first fastening mechanism connecting the sterile unit to the instrument drive unit and a second fastening mechanism connecting the sterile unit to the instrument. To improve the coupling between the sterile and instrument drive units, the transmission element has a conical region at a circumferential surface and the passageway orifice has a complementary conical region at a passageway wall. The conical regions are aligned coaxially and contact one another such that a rotation of the transmission element around the rotational axis relative to the base is blocked.

Claims

1. A sterile unit for the sterile connection of an instrument drive unit to a surgical instrument, comprising: a base with at least one circular passageway orifice, wherein a transmission element is arranged in the passageway orifice, which transmission element is supported so as to be rotatable around a rotational axis and axially movable in a direction of the rotational axis in a predetermined movement range between a first end position and a second end position, and a first fastening mechanism configured to connect the sterile unit to the instrument drive unit and a second fastening mechanism configured to connect the sterile unit to the instrument, wherein the transmission element has a conical region at a circumferential surface and the passageway orifice has a complementary conical region at a passageway wall, which conical regions are aligned coaxially relative to one another and contact one another in a positively-engaging and frictionally-engaging manner in the first end position such that a rotation of the transmission element around the rotational axis relative to the base is blocked.

2. The sterile unit according to claim 1, wherein the conical regions each form a frustum of a cone, wherein the cone has an apex angle of between 10° and 60°.

3. The sterile unit according to claim 1, wherein the conical region of the transmission element and/or the conical region of the passageway orifice are/is roughened or provided with a material which increases the friction coefficient.

4. The sterile unit according to claim 2, wherein the conical region of the transmission element and/or the conical region of the passageway orifice are/is roughened or provided with a material which increases the friction coefficient.

5. The sterile unit according to claim 1, wherein the transmission element is held in the passageway orifice by means of at least two snap hooks.

6. The sterile unit according to claim 2, wherein the transmission element is held in the passageway orifice by means of at least two snap hooks.

7. The sterile unit according to claim 3, wherein the transmission element is held in the passageway orifice by means of at least two snap hooks.

8. A manipulator for robotic surgery, comprising: an instrument drive unit, and a sterile unit for coupling with a surgical instrument, the sterile unit including a base with at least one transmission element which is arranged in a circular passageway orifice associated with the at least one transmission element and which is supported so as to be rotatable around a rotational axis and axially movable in a direction of the rotational axis in a defined movement range between a first end position and a second end position, and a first fastening mechanism by which the sterile unit is connected to the instrument drive unit, and wherein the instrument drive unit has one or more drives, a drive being associated with the at least one transmission element, wherein the drive has an engagement element, and the at least one transmission element has an engagement structure complementing the engagement element, and the transmission element is located in the second end position when the transmission element and the engagement element are aligned with one another rotationally around the rotational axis such that the engagement element engages in the engagement structure and transmits to the engagement structure a torque acting on the engagement element perpendicular to the rotational axis, and the transmission element is located in the first end position when the engagement element and the engagement structure are not aligned with one another, and wherein the transmission element has a conical region at a circumferential surface and the passageway orifice has a complementary conical region at a passageway wall, and wherein the conical regions come in contact in a positively engaging and frictionally engaging manner in the first end position such that a rotation of the transmission element around the rotational axis relative to the base is blocked.

9. The manipulator according to claim 8, wherein the conical regions each form a frustum of a cone, and wherein the cone has an apex angle of between 10° and 60°.

10. The manipulator according to claim 8, wherein a friction coefficient between the conical region of the transmission element and the conical region of the passageway orifice is greater than a friction coefficient between an underside of the transmission element and the engagement element.

11. The manipulator according to claim 9, wherein a friction coefficient between the conical region of the transmission element and the conical region of the passageway orifice is greater than a friction coefficient between an underside of the transmission element and the engagement element.

12. The manipulator according to claim 10, wherein the conical region of the transmission element and/or the conical region of the passageway orifice are/is roughened or provided with a material which increases the friction coefficient.

13. The manipulator according to claim 8, wherein the transmission element is held in the passageway orifice by at least two snap hooks.

14. The manipulator according to claim 9, wherein the transmission element is held in the passageway orifice by at least two snap hooks.

15. The manipulator according to claim 10, wherein the transmission element is held in the passageway orifice by at least two snap hooks.

16. The manipulator according to claim 11, wherein the transmission element is held in the passageway orifice by at least two snap hooks.

17. The manipulator according to claim 12, wherein the transmission element is held in the passageway orifice by at least two snap hooks.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The invention will be described in more detail in the following based on exemplary embodiments with reference to the accompanying drawings which likewise disclose features key to the invention. These embodiment examples are to be considered merely as illustrative and not restrictive. For example, it is not to be construed from a description of an embodiment example having a plurality of elements or components that all of these elements or components are necessary to its implementation. On the contrary, other embodiment examples can also contain alternative elements and components, fewer elements or components or additional elements or components. Elements or components of different embodiment examples can be combined unless stated to the contrary. Modifications and variations which are described for one of the embodiment examples may also be applicable to other embodiment examples. In order to avoid repetition, like or comparable elements are designated by like reference numerals in different figures and are not described repeatedly. The drawings show:

[0024] FIG. 1 a manipulator with an instrument drive unit, a sterile unit in a first embodiment, and a surgical instrument;

[0025] FIG. 2 the instrument drive unit, the sterile unit in a first embodiment and the surgical instrument in an exploded view;

[0026] FIG. 3A a second embodiment of the sterile unit in a first view;

[0027] FIG. 3B a second embodiment of the sterile unit in a second view;

[0028] FIG. 3C a detailed view of a transmission element;

[0029] FIG. 4 a sectional view of the second embodiment of the sterile unit.

DETAILED DESCRIPTION

[0030] FIG. 1 shows a robotic manipulator 50 with an instrument drive unit 20 and an instrument 30. Such manipulators 50 comprise a plurality of joints which allow the instrument 30 to be freely positioned in space. In this regard, they can be employed independently as aids for the surgeon, e.g., as endoscope holders, or in combination with a surgical telemanipulator. Since the area surrounding a patient to be operated on must always be sterile so as to prevent infections, parts of the system which are difficult to sterilize, i.e., the manipulator 50 and the instrument drive unit 20, are separated from the sterile zone by a sterile barrier 60. As described above, the sterile unit 10 shown here in a first embodiment is formed as an adaptor so that an end effector 35 of the instrument 30 can nevertheless by actuated.

[0031] FIG. 2 shows how the instrument 30, the first embodiment of the sterile unit 10 and the instrument drive unit 20 are arranged relative to one another. The sterile unit 10 has a base 11 and a plurality of transmission elements 12 which are supported so as to be rotatable around a rotational axis. The sterile unit 10 is arranged between the instrument 30 and the instrument drive unit 20.

[0032] The surgical instrument 30 comprises an instrument housing 31 and an instrument shaft 32. In this instance, there is no end effector 35 arranged at a distal end of the instrument shaft 32 because this is an endoscope. Generally, however, all types of instruments 30, for example, grippers, scissors, staplers, or dissectors, can be used with the corresponding end effectors 35. The quantity of degrees of freedom depends on the type of instrument 30. Apart from the movement of end effector joints, a mechanical triggering of additional functions, for example, the activation of a blade, is also included. As a rule, the quantity of degrees of freedom is between one, for example, for an endoscope, or five degrees of freedom for a stapler. However, the quantity of degrees of freedom is optional in principle and can be adapted to the specific case of application.

[0033] The instrument drive unit 20 comprises a drive housing 22 in which are accommodated five drives 21, each of which has an engagement element and a motor, not shown here, generally an electric motor which generates a torque. The engagement element is arranged outside of the drive housing 22. A more exact description follows below. The torque is transmitted by the respective engagement element to the transmission elements 12 which have an engagement structure complementing the engagement element. On the side facing the instrument 30, the transmission elements 12 are provided with a selected coupling structure by which the torque is conveyed to outputs of the instrument 30, not visible here, in order to move the end effector 35. In the present example, the coupling structure is formed as a knurled circumferential surface of the respective transmission element 12. However, other variants are also used in the art, all of which can also be applied here in place of the coupling structure.

[0034] In addition to the drives 21 and the drive housing 22, the instrument drive unit 20 comprises one or more first fastening elements 23 which fasten the sterile unit 10 to the instrument drive unit 20. For this purpose, a complementary first fastening mechanism or fastener, not visible in this drawing, is in turn provided at the sterile unit 10. Located on the side of the sterile unit 10 facing the instrument 30 is a second fastening mechanism 14 which in turn allows the surgical instrument 30 to be fastened to the sterile unit 10. This connection can be undone by means of a release mechanism 33.

[0035] FIGS. 3A and 3B show the sterile unit 10 in more detail in a second embodiment. Apart from the transmission elements 12 and the base 11, a first fastening mechanism 13 and a second fastening mechanism 14 are arranged on the sterile unit 10. The first fastening mechanism 13 which allows the sterile unit 10 to be fastened to the instrument drive unit 20 by means of the first fastening elements 23 located at the latter is disposed on the side of the sterile unit 10 which is associated with the instrument drive unit 20 and shown in FIG. 3B. The second fastening mechanism 14 which allows the surgical instrument 30 to be fastened to the sterile unit 10 via second fastening elements located at the instrument 30 is disposed on the side of the sterile unit 10 which faces the instrument 30 and can be seen in FIG. 3A. Both fastening mechanisms 13, 14 are parts of a snap-in connection, but the first fastening mechanism 13 and second mechanism 14 can generally be formed in any manner customary in the art insofar as the sterile unit 10 can be detachably or permanently connected to the instrument 30 and the instrument drive unit 20 by frictional engagement or positive engagement.

[0036] The transmission element 12 is shown in more detail in FIG. 3C and is inserted into a passageway orifice of the base 11. There are various possibilities for the concrete realization thereof. For example, the base 11 can be formed of two parts and the transmission element 12 is received between the two parts of the base 11. Alternatively, as is shown in FIGS. 3A, 3B and 3C, the transmission element 12 itself is outfitted with a fastening option. It can be formed itself of two bodies between which the base 11 is clamped, or it can be outfitted with fastening means which hold it on the base 11 so as to be rotatable around the rotational axis. The snap hooks 17 shown in FIG. 3C, ball joint connections or the like fastening means are suitable for this purpose.

[0037] Although not shown, other possibilities include differently shaped transmission elements 12 or an electric contact for conducting current signals through the sterile unit 10. Further, a fastening surface 15 is preferably provided at the side of the base 11 of the sterile unit 10 facing the instrument drive unit 20. In this case, a sterile sheeting is applied by means of glue or welding and, together with the sterile unit 10, forms a sterile barrier 60. Another possibility customary in the art for introducing the sterile sheeting consists in forming the base 11 from two parts so that the sterile sheeting is clamped between the two parts.

[0038] The transmission elements 12 have a coupling structure 16 at the upper side thereof which corresponds to the embodiment form in FIG. 2. At the underside which is visible in FIG. 3B, the transmission elements 12 have an engagement structure 19 for receiving an engagement element of the associated drive 21.

[0039] FIG. 4 shows a section through an instrument drive unit 20 connected to the sterile unit 10 at the location of a transmission element 12. The sterile unit 10 is fastened to the first fastening element 23 of the instrument drive unit 20 by means of the first fastening mechanism 13. In the present example, this is a snap-in connection. A sterile sheeting 60, not shown here, which is connected to the sterile unit 10 is arranged between the base 11 and the drive housing 22. The transmission element 12 is mounted in a passageway orifice and is held at the upper side by the snap hook 17. On the opposite side facing the instrument drive unit 20, the transmission element 12 has a first conical region 18a at a circumferential surface. Also located at the base 11 is a second conical region 18b on a passageway wall of the passageway orifice. The two conical regions 18a, 18b are oriented coaxially relative to one another and are complementary so that the transmission element 12 can engage with the base 11 in this location by positive engagement in a planar manner.

[0040] The transmission element 12 is movable axially in a predetermined movement range in direction of a rotational axis A between a first end position and a second end position. The end positions depend on the alignment of the engagement structure 19 with respect to an engagement element 25. In this instance, the engagement element 25 is formed as a cube-shaped pin, and the engagement structure 29 is formed as a slot into which the pin fits. Other suitable structures customary in the art are also contemplated. For example, a plurality of pins and complementary slots as well as cross-shaped, star-shaped or polygonal structures are also contemplated. The side walls of the engagement structure 19 and of the engagement element 25 are advantageously oriented parallel to the rotational axis A in order to ensure a good transmission of the torque introduced by the drive 21. An inverse arrangement in which, for example, the engagement structure 19 is formed as a pin and the engagement element 25 is formed as a slot into which the pin fits is also easily possible.

[0041] If the sterile unit 10 and the instrument drive unit 20 are connected to one another, the engagement structure 19 and the engagement element 25 are generally not aligned with one another and do not engage in one another. The transmission of a torque and, therefore, the driving of the surgical instrument 30 is accordingly impossible. The transmission element 12 rests by an underside on the engagement element 25 so that it is raised and located in the first end position. The complementary conical regions 18a, 18b are connected by positive engagement and frictional engagement in the first end position.

[0042] In order to transmit a torque from a motor 24 of the drive 21 of the instrument drive unit 20 to the transmission element 12, the engagement element 25 must be aligned with the engagement structure 19 so that they engage in one another. This is brought about by the conical regions 18a, 18b which act in a self-locking manner in the first end position by means of the positive engagement and frictional engagement. This effect can be further amplified by different friction coefficients and friction radii between the engagement element 25 and the engagement structure 19. The system is generally so configured that a first friction torque acting between the engagement element 25 and the underside of the transmission element 12 is less than a second friction torque acting between the conical regions 18a, 18b. If the conical regions 18a, 18b are described as a truncated cone, the cone from which the truncated cone is taken has an apex angle. The more acute this apex angle, the larger the first friction torque. If the apex angle falls short of a critical apex angle which is empirically approximately 8° to 10° and also depends on the selected materials, the transmission element 12 cannot disengage from the first end position without being acted upon by an external force, and an alignment is no longer possible. If, on the other hand, the apex angle is larger, the first friction torque decreases until the advantage resulting from the conical regions 18a, 18b empirically and also depending on the materials used when the angle of approximately 60° to 80° is exceeded can be forfeited. In addition, the friction coefficient between the conical region 18a of the transmission element 12 and the conical region 18b of the passageway orifice can be greater than the friction coefficient between the underside of the transmission element 12 and the engagement element 25. This can be achieved in that the conical region 18a of the transmission element 12 and/or the conical region 18b of the passageway orifice are/is roughened or provided with a material that increases the friction coefficient, while the underside of the transmission element 12 and the engagement element 25 are smooth.

[0043] If the complementary conical regions 18a, 18b are connected in positive engagement and frictional engagement, then either the transmission element 12 does not rotate around the rotational axis A while the engagement element 25 slides over the underside of the transmission element 12 or, alternatively, the transmission element 12 rotates slower than the engagement element 25. In both of these cases, the rotation of the transmission element 12 around the rotational axis A relative to the base 11 is blocked, and the engagement element 25 is continually adapted with respect to its position relative to the transmission element 12 through a rotation by means of the motor 24 because it rotates faster than the transmission element 12.

[0044] When a position is reached in which the transmission element 12 and the engagement element 25 are so oriented to one another rotationally around the rotational axis A that the engagement element 25 engages in the engagement structure 19, the transmission element 12 enters the second end position. The engagement element 25 is received by the engagement structure 19 so that a torque acting on the engagement element 25 perpendicular to the rotational axis A is transmitted to the engagement structure 19 and, accordingly, to the transmission element 12. Since the conical regions 18a, 18b are no longer connected by positive engagement and frictional engagement, friction torque no longer acts at this location, and the transmission element 12 can rotate freely about the rotational axis A and transmit the torque virtually without losses.

REFERENCE CHARACTERS

[0045] 10 sterile unit [0046] 11 base [0047] 12 transmission element [0048] 13 first fastening mechanism [0049] 14 second fastening mechanism [0050] 15 fastening surface [0051] 16 coupling structure [0052] 17 snap hook [0053] 18a, b conical region [0054] 19 engagement structure [0055] 20 instrument drive unit [0056] 21 drive [0057] 22 drive housing [0058] 23 first fastening element [0059] 24 motor [0060] 25 engagement element [0061] 30 surgical instrument [0062] 31 instrument housing [0063] 32 instrument shaft [0064] 33 release mechanism [0065] 35 end effector [0066] 50 manipulator [0067] 60 sterile barrier [0068] A rotational axis