DE102012212094A1 - Endoscopic instrument has elongate shaft and distal instrument head which is controlled from proximal instrument end, where joint is formed in shaft or between distal shaft end and instrument head - Google Patents

Abstract

The endoscopic instrument has an elongate shaft (1) and a distal instrument head (4) which is controlled from the proximal instrument end, where a joint (6) is formed in the shaft or between the distal shaft end and the instrument head. A unit is provided for pivoting a distal joint part with respect to a proximal joint part. A transmission unit is formed for transmitting a control function of the proximal instrument end to the instrument head. The transmission unit has an epicyclic gear, whose central axis coincides with a joint axis (7).

Description

The invention relates to an endoscopic instrument having the features specified in the preamble of claim 1.

Endoscopic instruments of this type are either provided on the proximal side with a handle via which various movement functions can be controlled or, as may be the case with more complex instruments, provided with a proximal connection device with which it can be connected to an arm of a robot system the individual functions are controlled by an electric motor. The robot system itself is then appropriately controlled, as is well known in the art. Such an instrument is for example off US 7,524,320 B2 known. This instrument has an elongate shaft, at the distal end of an instrument head is arranged, which is controllable from the proximal end of the instrument. For this purpose, a connecting device is provided on the proximal side, with which the instrument can be connected to a robot arm, via which all functions can then be controlled.

In order to increase the possibilities of movement of the distal instrument end, on which, for example, a tool in the form of a pair of scissors, forceps, a needle holder or the like is arranged, it is well known in the art for the distal shaft end or between the distal shaft end and the instrument head Provide joint to distract the instrument head relative to the shaft axis can. A problem with such joints is always the implementation of the control means with which distal instrument parts behind it are operated, for example, to open and close a pair of pliers on the instrument head or to rotate the instrument head. For this purpose, it is regularly necessary to provide transmission means for transmitting the control functions from the proximal end of the instrument to the instrument head. At the US 7,524,320 B2 Known instrument, this is done by means of cables, which are deflected in the region of the joint via corresponding roles.

A disadvantage of the transmission means described therein is that it is not possible to pivot the instrument head without affecting the other transmission means. While this is still tolerable in robotic applications, since a corresponding compensation can be done by an electric motor and automatically, so that this mutual influence of the control means does not appear to the user. However, this requires an increased control engineering effort, which is fundamentally disadvantageous. However, such influencing of the control means to each other is problematic when the instrument is to be operated by a proximal handle.

Against this background, the invention has the object, a generic endoscopic instrument in such a way that the aforementioned disadvantages are avoided, d. H. that it is possible to generate a pivoting movement between the instrument shaft and the instrument head, without affecting the control means carried out in this area.

This object is achieved according to the invention by an endoscopic instrument having the features specified in claim 1.

The endoscopic instrument according to the invention has an elongate shaft and a distal instrument head, which can be controlled from the proximal end of the instrument. It has a joint in the shaft or between the distal shaft end and the instrument head and means for pivoting a distal joint part with respect to a proximal joint part. Furthermore, transmission means are provided for transmitting at least one control function from the proximal end of the instrument to the instrument head. According to the invention, the transmission means are formed by at least one planetary gear whose central axis coincides with the hinge axis.

The solution according to the invention allows by purely mechanical means, namely a planetary gear, with a suitable design of the transmission pivotal movement of the joint, without the control means, typically pull wires or tie rods, move to each other. However, it can also, if desired, a targeted movement can be generated, depending on how the gear ratio is selected in the planetary gear. In addition, the planetary gear allows a translation of the control means, d. H. Depending on the ratio, the force can be increased or lowered in a targeted manner or the range of movement can be reduced or increased. Such a planetary gear, whose central axis coincides with the joint axis, can be compact and space-saving. In principle, the epicyclic gear can be designed as a friction gear but also as a gearing, in the latter higher forces can be transmitted in the rule, and also eliminates the occasional adjustment necessary in the case of friction wheels.

It is particularly advantageous if a planetary gear in the form of a gear transmission is used as planetary gear, which has at least one sun gear and at least one ring gear, wherein between sun and ring gear is particularly advantageous Planet wheels are provided, which are rotatably mounted in a planet carrier and which couple the sun gear with the ring gear. In this case, the planet carrier is advantageous rotatably connected to a hinge part and the ring gear rotatably connected to the other joint part. These connections provide the control functions which ensure that when pivoting the joint, the other control means in this area are mitverstellt so that the pivoting has neither influence on the handle side nor the distal instrument head or the tool located there.

According to one embodiment of the invention, a further ring gear and another planet carrier is provided with rotatably mounted therein planetary gears for transmitting a control function, wherein the coupling takes place with respect to the pivoting movement via a common sun gear which couples the ring gears and planetary gears in the planetary carriers together.

The arrangement described above is particularly advantageous since the connection of the control means lies at a clear radial distance to the axis of rotation of the joint or to the central axis of the transmission. However, in principle, a kinematic reversal is possible.

In this way, virtually any control functions can be transmitted by a further ring gear and another planet carrier is provided with rotatably mounted planetary gears for each control function, wherein the movement coupling takes place via the central sun gear.

In this case, the sun gear may be provided with a continuous spur toothing, but it is also a graduated design conceivable to adjust in this way the ratios between the individual control means individually.

It is particularly advantageous if the control function takes place via tension and / or pressure transmitters guided in the shaft, for example rods or wires which are each fixed to a ring gear or a planetary carrier at a distance from the axis of rotation of the joint. Such tension or pressure transmitters are state of the art and are also used in instruments of the prior art for transmitting the control functions.

It is particularly advantageous if a control function is transmitted in each case via a pair of guided in the shank Zug- / Druckstäben, which are articulated to two offset by about 180 ° arranged articulation points on the ring gear or on the planet carrier. Such a "double" control allows a nearly backlash-free and high-force transmitting control function, which is largely independent of the direction of movement due to their symmetrical to the hinge axis arrangement, so for example with a pair of pliers with the same force to open as to close can be used. It is particularly for the present application, in which a joint is provided which pivots a distal part of the instrument relative to the shaft axis, advantageous if the articulation points on the ring gear and the planet carrier have the same radial distance from the axis of rotation or optionally also a specifically different order in conjunction with the translation of the transmission to realize a suitable force-displacement transmission. The pivot points are advantageous also articulated to ensure a low-friction movement as possible. In particular, if a manual control of the instrument is to take place, it is advantageous to design the transmission ratio of the planetary gear so that a pivotal movement of the joint is independent of the transmission of the control functions. This is a particular advantage achieved by the planetary gear. It is understood that, for example, in robotic use of the instrument, d. H. If such a transfer function of the control function, which is independent of the pivoting movement, may possibly be dispensable, the epicyclic gearing according to the invention can also be used specifically for other purposes, for example if special gear ratios are to be realized in the control functions.

The movement coupling within the transmission between the pivoting movement of the joint and the corresponding compensating movements of the control means is effected by the central sun gear. In the simplest form, this is consistently designed with a uniform spur toothing, but it can also paragraphs are provided with different tooth pitches to realize certain gear ratios. The design options are virtually unlimited.

The invention is explained in more detail with reference to an embodiment shown in the drawing. Show it:

1 in a greatly simplified perspective representation of an endoscopic instrument according to the invention,

2 in a perspective view of the joint area in non-angled position,

3 the joint area in an angled position in representation after 2 .

4 the transmission structure in the joint area in representation accordingly 3 .

5 Joint and gear in exploded view and

6 Joint and gear in composite form in perspective view.

The endoscopic instrument is in its basic structure in 1 shown. It has an elongated shaft 1 on which proximal side an operating and control part 2 which is shown here only as a "black box". This can be an operating and control part 2 act like this for example US 7,524,320 B2 is known or even a manually operable control and control part 2 , as is the state of the art in endoscopic instruments in numerous constructive variants. The shaft 1 has a distal end region 3 on, at the end of an instrument head 4 connects, which is exemplified here as a pair of pliers. This instrument head 4 stands for any tool that comes from the proximal operating and control part 2 off is actuated.

The endoscopic instrument has a longitudinal axis 5 on, which through the longitudinal axis of the shaft 1 is determined. The instrument head 4 can from this longitudinal axis 5 be swung out, this is in the distal end 3 a joint 6 provided, the hinge axis 7 the longitudinal axis 5 vertical cuts. The structure of this joint is based on the 2 - 6 shown in detail.

The joint 6 serves to bend the instrument head 4 opposite the shaft 1 and is from the control and control section 2 out with regard to its pivot position controllable. It consists of a proximal joint part 8th , which is the outer contour of the shaft 1 continues and is firmly connected to this and a distal joint part 9 which in straight position also continues the outer contour of the shaft and fixed to the distal end of the shaft and the attached instrument head 4 connected is. The joint parts 8th and 9 are to the axis of rotation 7 of the joint out of their fully cylindrical material in each case to two mutually offset by 180 ° tongues 10 respectively. 11 except, with the tongues 10 of the proximal joint part 8th Continue the cylindrical outer contour, whereas the tongues 11 of the distal joint part 9 arranged inwardly offset so that they are between the tongues 10 can be incorporated, as this particular from the 2 . 3 and 6 evident. They each have a hole 12 on, which serves to receive a joint axis.

In the joint parts 8th and 9 are related to the straight position of the joint 6 parallel to the longitudinal axis 5 slots 13 provided, which for the guidance of pull / push rods 14 serve to control the angling of the joint and to control the instrument head 4 serve. To control the bending of the joint 6 ie the distal joint part 9 opposite the proximal joint part 8th and the shaft 1 are two relative to the axis of rotation 7 of the joint 6 offset by 180 ° to each other arranged push / push rods 14 provided only by the proximal joint part 8th are guided and end within the joint. The push / pull rods 14 are hinged at their distal ends to a ring gear H ₁ , which rotatably with the distal joint part 9 is connected and has an internal toothing, which is in engagement with planetary gears P ₁ , which are rotatably mounted in a ring-shaped planetary carrier T ₁ and centrally with a sun gear S comb. The planet carrier T ₁ is fixed to the proximal joint part 8th connected, forms on its outer periphery a bearing surface on which a tongue 11 with her hole 12 runs and thus the pivot bearing of the joint 6 forms.

The planet carrier T ₁ has three parallel to the hinge axis at the flat inner side facing the joint 7 arranged axle bolts 15 on, on which the planet gears P _{1 are} rotatably mounted. Since the planet carrier T ₁ fixed to the proximal joint part 8th and the ring gear H ₁ fixed to the distal joint part 9 can be connected by means of the push / pull rods 14 the pivoting movement of the distal joint part 9 with respect to the proximal joint part 8th to be controlled. Since during a pivoting movement of these components to each other, the planetary gears P ₁ roll on the internal toothing of the ring gear H ₁ , there is a corresponding rotational movement of the sun gear S, which meshes internally with the planetary gears P ₁ .

Via the sun gear S further transmission stages of the planetary gear thus formed are driven, which are provided for the transmission of further control functions.

In the illustrated embodiment, two more gear stages are provided, specifically for the transmission of movements, which also about 180 ° relative to the shaft axis 5 staggered pull / push rods 16 generated by the proximal control and control part 2 be moved out to a corresponding control function on the instrument head 4 , For example, the opening and closing of a pair of pliers are provided. These pull / push rods 16 are on the outer circumference of a planet carrier T ₂ offset by 180 ° to each other articulated, which is annular and also parallel to the hinge axis 7 laterally projecting axle bolts 20 has, on which planetary gears P ₂ rotatably mounted are, on the one hand with the central sun gear S comb and on the other hand with an internal toothing of a ring gear H ₂ , at its outer periphery also offset by 180 ° to each other two pull / push rods 17 are hinged, which the movements of the push / pull rods 16 continue to transfer to distal direction.

Parallel to the pull / push rods 14 and 16 are in the shaft 1 still push / push rods 18 guided, whose ends are articulated on the outer circumference of a planet carrier T ₃ offset by 180 ° to each other, which also parallel to the hinge axis 7 laterally projecting axle bolts 21 on which planetary gears P _{3 are} rotatably mounted, which mesh on the one hand with the central sun gear S and on the other hand with the internal teeth of a ring gear H ₃ , on the outer circumference of the distal ends of pull / push rods 19 are articulated offset by 180 °, which the movements of the push / pull rods 18 downwards, ie to the instrument head, transferred, and for example to rotate the head 4 serve around the shaft axis.

The transmission kinematics here consists of successively connected planetary gear stages. In the illustrated embodiment, the first gear stage from the gear H _1, the planet carrier T ₁ and the planetary gears P ₁ and the sun gear S. The number of teeth of the ring gear H ₁ is for _H1 and the number of teeth of the sun gear S is for _S. The planet carrier T ₁ is concentric to the hinge axis 7 firmly with the proximal joint part 8th connected and is on the outside with a bearing surface for the storage of the distal joint part 9 Mistake. The ring gear H ₁ is fixed to the distal joint part 9 connected. In addition, the ring gear H ₁ on the outer circumference joints, where the pull / push rods 14 are articulated. Become the push / pull rods 14 moves, so the movement is transmitted to the ring gear H ₁ and the planetary gears P ₁ on the planetary carrier T ₁ , the fixed to the distal joint part 9 connected is. The distal joint part 9 will then be around the hinge axis 7 pivoted. Since the planet carrier T ₁ fixed to the proximal joint part 8th is connected, the rotation of the ring gear H ₁ simultaneously causes a rotation of the sun gear S with the gear ratio i ₁ = -z _S / z _H1 . Become the push / pull rods 14 moved, so are the push / push rods 16 and 18 and thus the planet carrier T ₂ and T ₃ still. Since the common sun gear S rotates, this rotational movement with the ratio i ₂ = -z _H2 / z _{S is} transmitted to the ring gear H ₂ , where z _{H2 is} the number of teeth of the ring gear H ₂ . If i ₁ = i ₂ , or for a common sun gear z _H1 = z _H2 , then for the transmission of motion from H ₁ to H ₂ for the total ratio iges = i ₁ × i ₂ = 1. The ring gear H ₂ therefore rotates relatively to the proximal joint part 8th the same distance as the ring gear H ₁ and the distal joint part 9 , This leaves the relative positions of the push / pull rods 17 and 19 to the distal joint part 9 obtained, ie the pivotal movement of the joint 6 has no influence on the motion transmission. In the exemplary embodiment, therefore, the current pivot position of the pliers and the rotational position of the head remain independent of the pivot position of the joint.

Hierdurch ergibt sich zwangsläufig eine Übersetzung. Bei einem praktikablen Zähnezahlverhältnis von z. B. z_S = 1/2 z_H ergibt sich daraus ein Übersetzungsverhältnis i_2A = 2 / 3 . Bei z_S = 1 / 3 z_H ist i_2A = 3 / 4 . Es findet also eine leichte Übersetzung der Drehbewegung des Planetenträgers T₂ auf das Hohlrad H₂ statt. Für die Übertragung der Bewegungen der Zug- / Druckstangen 18 und 19 bzw. für das Hohlrad H₃ und den Planetenträger T₃ gilt das vorbeschriebene Verhältnis entsprechend.To transfer the movement of the push / pull rods 16 and 18 on the push / pull rods 17 and 19 the second and third stage of the planetary gear are provided. A movement of the push / pull rods 16 is transmitted in a rotational movement of the planet carrier T ₂ , the rotation causes now with a fixed sun gear S, a rotational movement of the ring gear H ₂ with the translation

This inevitably results in a translation. At a practical teeth ratio of z. B. z _S = 1/2 z _H results from a transmission ratio i _2A = 2/3 , at z _S = 1/3 z is _H i _2A = 3/4 , So there is a slight translation of the rotational movement of the planet carrier T ₂ on the ring gear H ₂ instead. For the transmission of the movements of the push / pull rods 18 and 19 or for the ring gear H ₃ and the planet carrier T ₃ , the prescribed ratio applies accordingly.

If a motion reduction is desired, then the structure described above by an otherwise combination of sun gear, planet carrier and ring gear with the joint parts 8th and 9 respectively. For example, the proximal joint part 8th firmly connected to the ring gear H ₁ and the planet carrier T ₁ fixed to the distal joint part 9 get connected. The push / pull rods 16 are then with the ring gear H ₂ and the output side pull / push rods 17 to connect with the planet carrier T ₂ . In addition, the number of teeth of the gears can be varied according to the desired gear ratios.

Instead of the pull / push rods and rope drives can be used, which surround the corresponding peripheral surfaces or are fixed to this. Thus, by varying the ratios of the planetary gear effects can be achieved that, for example, the force of the forceps is significantly increased or the movement stroke. An adaptation of the transmission to the specific application requirements can be done in this way.

LIST OF REFERENCE NUMBERS

1

shaft

2

Operating and control part

3

distal end region

4

instrument head

5

longitudinal axis

6

joint

7

joint axis

8th

proximal joint part

9

distal joint part

10

Tongues of 8th

11

Tongues of 9

12

Hole in the tongues

13

slots

14

Pull / push rods

15

Axle pin of P ₁

16

Pull / push rods

17

Pull / push rods

18

Pull / push rods

19

Pull / push rods

20

Axle pin of P ₂

21

Axle pin of P ₃

T ₁ -T ₃

planet carrier

P ₁ -P ₃

planetary gears

H ₁ -H ₃

ring gears

S

sun

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 7524320 B2 [0002, 0003, 0024]

Claims (9)

Endoscopic instrument with an elongated shaft ( 1 ) and a distal instrument head ( 4 ), which is controllable from the proximal end of the instrument, with a joint ( 6 ) in the shaft ( 1 ) or between the distal shaft end and the instrument head ( 4 ), with means for pivoting a distal joint part ( 9 ) with respect to a proximal joint part ( 8th ), and with transmission means for transmitting at least one control function from the proximal end of the instrument to the instrument head ( 4 ), characterized in that the gear means comprise at least one planetary gear, the central axis ( 7 ) with the hinge axis ( 7 ) coincides. Instrument according to claim 1, characterized in that the planetary gear is a planetary gear with at least one sun gear (S), with at least one ring gear (H ₁ ) and in between at least one planet carrier (T ₁ ) rotatably mounted planetary gears (P ₁ ), which Sun gear (S) and ring gear (H ₁ ) coupled to each other motion, and that the planet carrier (T ₁ ) rotationally fixed with a hinge part ( 8th ) and the ring gear (H ₁ ) rotationally fixed with the other joint part ( 9 ) connected is. Instrument according to claim 1 or 2, characterized in that for transmitting a control function, a further ring gear (H ₂ , H ₃ ) and another planet carrier (T ₂ , T ₃ ) with rotatably mounted therein planetary gears (P ₂ , P ₃ ) is provided , wherein a common sun gear (S) is provided, which couples the ring gears (H) and the planet gears (P) in the planet carriers (T). Instrument according to one of the preceding claims, characterized in that for transmitting further control functions further ring gears (H) and further planet carrier (T) are rotatably mounted therein planet gears (P) are provided, which are coupled in motion via the common sun gear (S). Instrument according to one of the preceding claims, characterized in that a control function in the shaft ( 1 ) guided tension and / or pressure transmitters ( 14 ; 16 - 19 ) takes place, each at a ring gear (H) or a planet carrier (T) at a distance from the axis of rotation ( 7 ) of the joint ( 6 ). Instrument according to one of the preceding claims, characterized in that a control function via a respective pair of guided in the shank Zug- / Druckstäben ( 16 - 18 ) is transmitted, which are articulated at two offset by 180 ° arranged articulation points on the ring gear (H) or on the planet carrier (T). Instrument according to one of the preceding claims, characterized in that the articulation points on the ring gear (H) and on the planet carrier (T) the same radial distance from the axis of rotation ( 7 ) exhibit. Instrument according to one of the preceding claims, characterized in that the transmission ratio of the planetary gear is designed so that a pivoting movement of the joint ( 6 ) is independent of the transfer of the control functions. Instrument according to one of the preceding claims, characterized in that the sun gear (S) is offset.

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