Surgical instrument

Abstract

The present disclosure relates to a surgical instrument (1) for surgically grasping, pinching, and / or cutting tissue in a living body, the surgical instrument (1) comprising: - an actuating device (3) having two handle parts (5, 7), at least a first handle part (5) of the two handle parts (5, 7) being mounted so as to be translatable and / or rotatable in an opening direction and a closing direction with respect to a second handle part (7) of the two handle parts (5, 7); - a tool head (11) having two tool parts (13, 15), at least a first tool part (13) of the two tool parts (13, 15) being mounted so as to be translatable and / or rotatable in an opening direction and a closing direction with respect to a second tool part (15) of the two tool parts (13, 15); - a shaft (9) extending along a longitudinal axis (X) between the actuating device (3) and the tool head (11), a proximal end of the shaft being connected or connectable to the actuating device (3) and a distal end of the shaft being connected or connectable to the tool head (11), the shaft (9) having an axially movable transmission element (17) for transmitting a manual force (F H ) in the opening and closing directions from a first handle part (5) to a first tool part (13); - an overload protection device (19) having a spring element (21) for limiting a manual force (F H ) in the closing direction transmitted to the first tool part (13); and being provided with. The surgical instrument (1) is characterized in that the overload protection device (19) has a toggle lever mechanism (23), and the spring element (21) biases the transmission element (17) in the closing direction via the toggle lever mechanism (23).

Description

Technical Field

[0001] The present disclosure relates to a surgical instrument for surgically grasping, pinching, and / or cutting tissue in a living body, particularly a laparoscopic instrument.

Background Art

[0002] For example, surgical instruments for endoscopic surgery such as laparoscopic instruments are often designed to be as thin as possible so that surgical procedures can be performed with as little invasion to the patient as possible. The tool head of such a surgical instrument typically has relatively delicate tool parts such as, for example, the gripping part of (grasping) forceps or scissors blades. Therefore, if the manual force transmitted to the tool head becomes very large, there is a risk that the delicate tool part will be damaged.

[0003]

[0004] Such overload protection devices are known, for example, from German Patent Invention No. 10110106, German Patent Invention No. 10328514, German Utility Model No. 29917554, US Patent Application Publication No. 5,009,661, German Patent Invention No. 4411099, German Utility Model No. 29713490.

[0005] However, known overload protection devices have the disadvantage that the manual force transmitted to the tool head is relatively small when the opening angle of the tool is small. Therefore, in some cases, it may be impossible to grasp, pinch, and / or cut small tissue pieces with the required force. In particular, in the case of a forceps grip (Pinzettengriff) where the distal end of the tool head is frequently used, the gripping force, pinching force, or cutting force becomes particularly small.

[0006] ​The reason is that the spring characteristic curve of the spring, which is usually used as an overload protection device, is a straight line passing through the origin, and the spring has only a small spring force at the start of the deflection of the spring. When the opening angle of the tool is small and the further movement of the operating lever is not sufficient to increase the spring force, the manual force transmitted to the tool head remains relatively small. Therefore, there is a possibility that small tissue pieces may slip off from the tweezer grip, may not be grasped well, or may not be separated.

Summary of the Invention

Problems to be Solved by the Invention

[0007] An object of the present invention is, on the one hand, to protect the tool head of a surgical instrument from overload, and on the other hand, to provide transmission of a force of sufficient magnitude even when the opening angle of the tool is small.

Means for Solving the Problems

[0008] This problem is solved by the subject matter of independent claim 1. Preferred embodiments can be understood from the dependent claims, the following description, and the figures.

[0009] According to the present disclosure, there is provided a surgical instrument for surgically grasping, pinching, and / or cutting tissue in a living body, the surgical instrument comprising - an operating device having two handle parts, at least a first handle part of the two handle parts being attached to a second handle part of the two handle parts so as to be translatable and / or rotatable in an opening direction and a closing direction, - a tool head having two tool parts, at least a first tool part of the two tool parts being attached to a second tool part of the two tool parts so as to be translatable and / or rotatable in an opening direction and a closing direction, A shaft extending along the longitudinal axis between the actuating device and the tool head, having a proximal end connected or connectable to the actuating device and a distal end connected or connectable to the tool head, and having an axially movable transmission element for transmitting manual force in the opening and closing directions from a first handle part to a first tool part. - An overload protection device having a spring element for limiting the manual force in the closing direction transmitted to the first tool part. The surgical instrument is characterized in that the overload protection device has a toggle lever mechanism and the spring element biases the transmission element in the closing direction via the toggle lever mechanism.

[0010] Due to the biasing, regardless of the opening angle of the tool head, sufficient force transmission to the tool can be ensured simultaneously with the start of deflection of the spring element. This means that even when the opening angle of the tool head is small, at least the biasing force of the spring element is transmitted to the tool. By appropriately designing the parameters of the toggle lever mechanism and the spring element, a desired biasing force can be ensured, whereby even very small tissue pieces can be properly pinched and / or cut with a forceps grip and will not slip out of the forceps grip (Zangengriff).

[0011] Another advantage of the toggle lever mechanism is that in the case of large tissue pieces that require a large opening angle of the tool head, the force transmission to the tool due to spring displacement can be reduced. That is, in the case of large tissue pieces, a forceps grip by the distal end of the tool head is not required, and in the central or proximal region of the tool part used, due to the lever action, the required force is basically reduced. Furthermore, in practice, large and hard tissue pieces are of little use.

[0012] Optionally, the toggle lever mechanism can be articulated to the transmission element at the bending point. This is advantageous for transmitting the force from the spring element to the transmission element in the direction of the longitudinal axis with a structure that is as simple as possible for the toggle lever mechanism and with a minimum number of component types.

[0013] Optionally, the toggle lever mechanism may have two distal support points spaced radially from the longitudinal axis and be articulately connected to two spring bends of the spring element via the two distal support points. Thereby, a structure of an overload protection device substantially symmetric with respect to the longitudinal axis can be realized, and the spring force can be evenly distributed to the two spring bends. The spring bends can be part of an integral spring element, and when the spring element flexes, the spring bends elastically pivot radially outward. That is, the spring element can form a proximal solid joint (Festkoerpergelenke) having two elastic parts, and the spring bends extend from the solid joint to the respective distal support points.

[0014] Optionally, the bending point can be arranged proximal to the distal support point. Thereby, the toggle lever mechanism defines an opening angle that opens distally at the bending point. When the distal support point is pulled proximally in the closing direction and the bending point senses the resistance to the closing movement caused by the tissue piece in the tool, the opening angle of the toggle lever mechanism increases against the spring force of the spring element.

[0015] Optionally, the spring element may have a proximal support point and be articulately connected to a first handle part via the proximal support point. This proximal support point is preferably located on the longitudinal axis of the shaft, moves proximally in the closing direction, and moves distally in the opening direction. At the proximal support point, when the first handle part is moved in the closing direction, the first handle part preferably pulls the spring element proximally.

[0016] Optionally, the proximal support point can be arranged proximal to the bending point. At the bending point, the spring element pulls the transmission element proximally in the closing direction via the toggle lever mechanism. When the transmission element moves proximally, the tool part of the tool head closes.

[0017] Optionally, the spring element may be coupled to the first handle part such that when further movement of the first tool part in the closing direction is blocked by the tissue, it immediately expands radially outward against its spring tension to open the toggle lever mechanism. Preferably, the frictional resistance to the movement of the transmission element and the tool part is very small, and the spring element does not expand without the tissue blocking the tool part.

[0018] Optionally, the spring element may have two spring bends extending laterally opposite to the longitudinal axis from the first handle part to the toggle lever mechanism. Thereby, a design of an overload protection device substantially symmetric with respect to the longitudinal axis can be achieved, and the spring force can be evenly distributed to the two spring bends.

[0019] Optionally, the spring element may have a guide opening extending along the longitudinal axis, and a bending point is axially movably attached to the guide opening in a guided state. The opening angle range of the toggle lever mechanism, and thus the deflection range of the spring element, can be defined by the length and position of the guide opening. For example, when the bending point is located at the proximal end of the guide opening, the opening angle of the toggle lever mechanism, and thus the deflection of the spring, is minimized. For example, when the bending point is located at the distal end of the guide opening, the opening angle of the toggle lever mechanism, and thus the deflection of the spring, is maximized. The guide opening is preferably an elongated hole of the spring element and extends along the longitudinal axis. By making the bending point abut against the distal end of the guide opening, excessive tension on the inelastic region of the spring element can be eliminated. By appropriately setting the position of the proximal end of the guide opening and the length of the lever member of the toggle lever mechanism, the spring element can be biased. This means that it is necessary to overcome the biasing force to move the bending point from the proximal end of the guide opening to the distal side.

[0020] Optionally, when the toggle lever mechanism is at its minimum opening angle, the spring element can be biased by a biasing force, such that when further movement of the first tool part in the closing direction is blocked by the tissue, immediately the opening angle of the toggle lever mechanism expands against the biasing force. Preferably, the manual force transmitted to the first tool part in the closing direction can be greater than the biasing force in a first opening angle range of the toggle lever mechanism and less than the biasing force in a second opening angle range of the toggle lever mechanism that is greater than the first opening angle range. This is because in the case of large tissue pieces, a forceps grip is not required and the force required for the tool is reduced. A force that varies only within a relatively small range can be transmitted to the transmission element over the entire opening angle range of the toggle lever mechanism, or over the entire spring displacement, or over the entire path of the bending point within the guide opening.

[0021] Optionally, the toggle lever mechanism can have two lever members of the same length that are articulately connected to each other at the bending point. The length of the lever members is greater than the axial movement range of the bending point relative to the proximal support point of the spring element where the spring element is articulately connected to the first handle element. Alternatively, when the bending point is mounted in a state where it is guided in the direction of the longitudinal axis, the toggle lever mechanism can also have only one lever member. However, two lever members arranged symmetrically with respect to the longitudinal axis have the advantage that lateral forces are substantially canceled out by each other and do not need to be absorbed by the guide.

[0022] The axial movement range of the bending point relative to the proximal support point of the spring element is preferably determined by the length of the guide opening of the spring element. The longer the length of the lever member, the flatter the curve of the force transmitted to the transmission element as a function of the position of the bending point within the guide opening can be. Such a flat force curve is desirable to make the force transmitted to the transmission element as constant as possible. Alternatively or additionally, a flat force curve can be achieved by a low spring constant of the spring element, provided that the minimum value for the required biasing is not exceeded. It is also advantageous for a flat force curve if the minimum opening angle of the toggle lever mechanism is as large as possible, i.e., when the bending point is at the proximal end of the guide opening, and in this case as well, the desired biasing sets the upper limit.

[0023] Optionally, the tool head can form pliers, scissors, and / or gripping forceps.

[0024] Optionally, the second handle part can be fixedly connected to or connectable to the shaft.

[0025] Optionally, when the first tool part hits the closing position against no tissue being blocked, the first handle part may be made to hit the closing position. In this case, no overload is applied to the tool head without tissue being blocked. Further, when picking up, pinching, or cutting a small piece of tissue, the axially moving range of the bending point within the guide opening can be made substantially shorter than the range allowed by the length of the guide opening. In this regard, for small tissue pieces, only the short section of the force curve that starts with the biasing force and then extends as flat as possible is relevant.

[0026] Hereinafter, the present disclosure will be described in more detail based on the accompanying drawings.

Brief Description of the Drawings

[0027]

Fig. 1a

Fig. 1b

Fig. 2

Fig. 3

Fig. 4

Fig. 5

Fig. 6a

Fig. 6b

Mode for Carrying Out the Invention

[0028] Figures 1a and 1b show a surgical instrument 1 in the form of a laparoscopic forceps, which is almost closed in Figure 1a and widely open in Figure 1b. This instrument has an actuating device 3 that can be operated by hand, and the actuating device 3 includes two handle parts 5 and 7 that can be grasped with one hand like pliers. The first handle part 5 of the two handle parts 5 and 7 can be moved by the user's thumb relative to the stationary second handle part 7 of the two handle parts 5 and 7. For this purpose, the first handle part 5 is pivotally attached to the second handle part 7. A shaft 9 extends distally from the stationary second handle part 7 to a tool head 11 along the longitudinal axis X of the surgical instrument 1. In this example of the embodiment, the tool head 11 is a forceps head having two tool parts 13 and 15 designed here as forceps gripping parts (jaw parts). At least the first tool part 13 of the two tool parts 13 and 15 is pivotally attached to the second tool part 15 of the two tool parts 13 and 15. In some cases, it is also possible for both tool parts 13 and 15 to be pivotally attached to the shaft 9. In Figure 1b, a relatively large tissue piece 16 is shown between the two tool parts 13 and 15. In Figure 1a, the tissue piece 16 is too small to be seen.

[0029] Within the shaft 9, a transmission element 17 in the form of a pull / push rod extends for transmitting manual force from the first handle part 5 to the first tool part 13 and / or the second tool part 15, and the transmission element 17 is movable within the shaft 9 along the longitudinal axis X. The transmission element 17 is coupled to the first handle part 5 on the proximal side and at least to the first tool part 13 on the distal side. When the handle parts 5 and 7 are manually closed in the closing direction, the transmission element 17 is displaced distally within the shaft 9, and due to this displacement, the tool parts 13 and 15 are closed. When the handle parts 5 and 7 are opened in the opening direction, the transmission element 17 is displaced proximally within the shaft 9, and due to this displacement, the tool parts 13 and 15 are opened. In this way, the user's manual force is transmitted to the tool head 11, and the tool parts 13 and 15 can be moved precisely as desired.

[0030] To protect the tool head 11 from overload due to excessive manual force of the user, the surgical instrument 1 includes an overload protection device 19 having a spring element 21 that limits the manual force transmitted in the closing direction to the first tool part 13. Different from the overload protection device known from the prior art in which simply a spring between the handle part and the transmission element is compressed with a certain force or more, the overload protection device 17 according to the present disclosure has a toggle lever mechanism 23 through which the spring element 21 biases the transmission element 17 in the closing direction, that is, proximally toward the first handle part 5 with a biasing force F0. The biasing force F0 in the closing direction is as follows,

Number

[0031] FIG. 2 shows in enlarged view the proximal portion of the surgical instrument 1 provided with the actuating device 3 and the overload protection device 19 to show the overload protection device 17 in more detail. When the first handle part 5 is pushed in the closing direction toward the second handle part 7, the proximal support point C moves proximally. The spring element 21 is pivotally connected to the first handle part 5 at the proximal support point C. Therefore, the spring element 21 is pulled proximally in the closing direction by the first handle part 5. The spring element 21 is curved symmetrically in an M shape and has two spring bends 25 extending distally from the proximal support point C on opposite sides in the lateral direction of the longitudinal axis X. One distal support point B is disposed at the distal end of each of the spring bends 25.

[0032] The toggle lever mechanism 23 has two lever members (link members) 27 of the same length, which are arranged between the distal support points B, B and are articulated to each other at the flexion point A. The flexion point A is substantially on the longitudinal axis X, similar to the proximal support point C, and is located near the distal support point B. Therefore, the toggle lever mechanism 23 has an opening angle 2α that opens distally. The flexion point A is the support point of the proximal end of the transmission element 17, and the transmission element 17 moves only when the flexion point A moves.

[0033] To guide the movement of the flexion point A with respect to the spring element 21, the spring element 21 has a guide opening 29 in the form of a long hole extending along the longitudinal axis X, and the flexion point A is attached within this long hole. The long hole 29 can be well recognized in FIGS. 3 to 6a. Unless the tissue 16 between the tool parts 13, 15 forms a resistance to closing, the flexion point A does not move distally within the guide opening 29, and the spring element 21 pulls the flexion point A proximally in the closing direction via the toggle lever mechanism 23. The frictional force within the surgical instrument 1 for moving the tool parts 13, 15 needs to be small so that the overload protection device 19 does not operate unless the tissue 16 between the tool parts 13, 15 forms a resistance to closing.

[0034] The flexion point A is biased to a proximal position within the guide opening 29 by the spring element 21. This means that, as shown, the length L of the lever member 27 and the position of the guide opening 29 are selected such that when the flexion point A is located at the proximal end within the guide opening 29, the spring bend 25 is already slightly deflected and acts radially inward to receive the biasing force F0. For the flexion point A to move distally within the guide opening 29, it is necessary to overcome this biasing force F0 and for the opening angle 2α of the toggle lever mechanism 23 to widen against the spring force of the spring element 21. In that case, the distal support point B is pushed radially outward against the spring force of the spring element 21.

[0035] On the one hand, the movement range of the first handle part 5 is restricted, and on the other hand, it is important to understand that the overload protection device 19 operates only when resistance is formed against the closing of the tissue 16 between the tool parts 13, 15. The biasing force F0 of the overload protection device 19 can hold and pinch or cut a very small tissue piece 16 between the tool parts 13, 15 with a desired minimum force, but there is only a small margin for operating the first handle part 5. As the opening angle 2α of the toggle lever mechanism 23 increases, the manual force transmitted to the transmission element 17 decreases. However, a larger opening angle 2α of the toggle lever mechanism 23 occurs only in the case of large and hard tissue pieces 16 and actually plays little role. Further, a larger tissue piece 16 can be at least partially gripped at the central and proximal portions of the tool parts 13, 15, where the lever is shorter, so the gripping force, pinching force, or cutting force becomes larger. The present disclosure aims to improve the tweezer grip of the small tissue piece 16 at the most distal end of the tool parts 13, 15, which is actually relevant in many cases, without sacrificing overload protection.

[0036] FIG. 5 shows the forces acting on the overload protection device 19. In order to pull the spring element 21 proximally at the proximal support point C, a manual force F is applied by the first handle part 5 G in the closing direction. When this force is applied, it is distributed by the two distal support points B, where a force F G / 2 acts proximally respectively. The spring force F F of the spring element 21 acts radially inward respectively, and as a result, an intermediate force F B is generated along the lever member 27 towards the bending point. As soon as the tissue piece 16 between the tool parts 13, 15 forms sufficient resistance to closing and the spring element 21 deflects, the force F H

Number

[0037] Figure 6b shows a force curve diagram comparing the spring force F F , the intermediate force F B , and the force F transmitted to the transmission element 17 H as a function of the instantaneous axial distance b between the distal support point B and the bending point A, compared to the force transmitted by a spring of the prior art (SdT). Since the distance b decreases as the overload protection device 19 operates, b decreases towards the right of the figure. When the bending point A is at the proximal end of the guide opening 29, the distance b at the start of operation of the overload protection device 19 is approximately 3.3 mm. The minimum opening angle 2α of the corresponding toggle lever mechanism 23 is approximately 120°, and half of the opening angle α is at least approximately 60°.

[0038] When there is a large and hard tissue piece 16 between the tool parts 13, 15, when the spring deflects at the maximum deflection a and the bending point A abuts against the distal end of the guide opening 29, the distance b becomes approximately 0.8 mm. That is, the guide opening 29 allows the bending point A to move a maximum of 2.5 mm within the guide opening 29. Correspondingly, the movement range of the first handle part 5 is limited so that the proximal support point C can also move axially by no more than 2.5 mm. This means that the spring element 21 cannot directly apply a proximal tensile force to the transmission element 17 at the distal end of the guide opening 29 via the toggle lever mechanism 23. That is, at the distal end of the guide opening 29, the first handle part 5 also stops in the closed position. At the same time, in this situation, the spring deflection a and the opening angle 2α of the toggle lever mechanism 23 are at most approximately 166°, and half of the opening angle α is at most approximately 83°. In this example, the length L of the lever member is approximately 6.6 mm.

[0039] Figure 6b shows the force profile of the force transmitted by a spring of the prior art (SdT) as a long dashed line as a straight line that steadily rises from the operation of the overload protection device to the maximum spring deflection. In contrast, the force F H transmitted to the transmission element 17 has a completely different profile due to the biasing force F0 of the spring element 21 via the toggle lever mechanism 23 biasing the transmission element 17 in the closing direction. The spring force F F and the intermediate force F B ​

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[0040] The curved region of the small distance b and the large opening angle 2α of the toggle lever mechanism 23 only occurs when there is a large and hard tissue piece 16 between the tool parts 13, 15. Therefore, what is actually particularly relevant is the initial curved region of the large distance b and the small opening angle 2α of the toggle lever mechanism 23. In the case of a small tissue piece 16, the overload protection device 19 does not operate in most of the available path when the first handle part 5 closes. For example, in an extreme case, since the tissue piece 16 is very small, there is very little space left until the handle part 5 abuts against the second handle part 7, and if the proximal support point C can only be pulled proximally by 1 mm, the force curve only relates to the range of the distance b from 3.3 mm to 3.2 mm. In the simple spring compression of the prior art (SdT) as overload protection, the manual force F H is hardly transmitted (see the long dashed line).

[0041] The force F transmitted to the transmission element 17 H In order to keep the curve of as flat as possible, the length L of the lever member 25 needs to be selected as large (long) as possible within the range of other design limits. In order to pinch the small tissue piece 16 as powerfully as possible with the forceps grip, the spring constant should be made as small as possible and the preloading force F0 should be made as large as possible. Increasing the minimum opening angle 2α of the toggle lever mechanism 23 is advantageous because the maximum spring force F F can be suppressed as small as possible, and the structural load on the system components can be suppressed as small as possible.

Explanation of reference signs

[0042] 1 Surgical instrument 3 Actuating device 5 First handle part 7 Second handle part 9 Shaft 11 Tool head 13 First tool part 15 Second tool part 16 Tissue piece 17 Transmission element 19 Overload protection device 21 spring element 23 toggle lever mechanism (Kniehebelmechanismus) 25 spring bend 27 lever member 29 guide opening A bending point B distal support point C proximal support point X longitudinal axis L length of the lever member Axial distance between the bending point B and the distal support point F H Manual force transmitted to the transmission element F G Manual force acting on the proximal support point F F Spring force F B Intermediate force F0 biasing force 2α Opening angle of the toggle lever mechanism

Claims

1. A surgical instrument (1) for surgically grasping, pinching, and / or cutting tissue within a living body, - An actuator (3) having two handle parts (5, 7), wherein at least the first handle part (5) of the two handle parts (5, 7) is mounted to the second handle part (7) of the two handle parts (5, 7) so as to be able to translate and / or rotate in the opening and closing directions, - A tool head (11) having two tool parts (13, 15), wherein at least the first tool part (13) of the two tool parts (13, 15) is mounted to the second tool part (15) of the two tool parts (13, 15) so as to be able to translate and / or rotate in the opening and closing directions, - A shaft (9) extending along the longitudinal axis (X) between the actuator (3) and the tool head (11), the proximal end being connected to or connectable to the actuator (3), and the distal end being connected to or connectable to the tool head (11), and the first handle component (5) to the first tool component (13) in an opening and closing direction by manual force (F Ｈ A shaft (9) having a transmission element (17) that is movable in the axial direction for transmitting ) - A spring element (21) is provided, and a manual force (F) in the closing direction is transmitted to the first tool part (13). Ｈ An overload protection device (19) to limit the load, Equipped with, The surgical instrument (1) is characterized in that the overload protection device (19) has a toggle lever mechanism (23), and the spring element (21) biases the transmission element (17) in the closing direction via the toggle lever mechanism (23).

2. The surgical instrument (1) according to claim 1, wherein the toggle lever mechanism (23) is articulated to the transmission element (17) at the bending point (A).

3. The surgical instrument (1) according to claim 1 or 2, wherein the toggle lever mechanism (23) has two distal support points (B) radially separated from the longitudinal axis (X), and is articulated to each of the two spring-curved portions (25) of the spring element (21) via the two distal support points (B).

4. The surgical instrument (1) according to claim 3, as dependent on claim 2, wherein the bending point (A) is located proximal to the two distal support points (B).

5. The surgical instrument (1) according to claim 1 or 2, wherein the spring element (21) has a proximal support point (C) and is articulated to the first handle component (5) via the proximal support point (C).

6. The surgical instrument (1) according to claim 5, as dependent on claim 2, wherein the proximal support point (C) is located proximal to the bending point (A).

7. The surgical instrument (1) according to claim 1, wherein the spring element (21) is coupled to the first handle component (5) such that when further closing movement of the first tool component (13) is blocked by tissue (16), it immediately expands radially outward against its own spring tension to open the toggle lever mechanism (23).

8. The surgical instrument (1) according to claim 1, wherein the spring element (21) has two spring curves (25) extending from the first handle component (5) to the toggle lever mechanism (23) on the opposite side of the longitudinal axis (X).

9. The surgical instrument (1) according to claim 2, wherein the spring element (21) has a guide opening (29) extending along the longitudinal axis (X), and is mounted so as to be movable in the axial direction with the bending point (A) guided within the guide opening (29).

10. The toggle lever mechanism (23) has a minimum opening angle (2α ｍｉｎ When the spring element (21) is in the state of (F), the biasing force (F ０ When biased by (F), and further movement of the first tool component (13) in the closing direction is prevented by the structure (16), the opening angle (2α) of the toggle lever mechanism immediately changes to the biasing force (F ０ A surgical instrument (1) according to claim 1, which expands against )

11. A manual force (F) is transmitted to the first tool component (13) in the closing direction. Ｈ ) in the first opening angle range of the toggle lever mechanism (23) the biasing force (F ０ In the second opening angle range of the toggle lever mechanism (23), which is larger than the first opening angle range, the biasing force (F ０ A surgical instrument (1) according to claim 10, which is smaller than ).

12. The surgical instrument (1) according to claim 2, wherein the toggle lever mechanism (23) has two lever members (27) of the same length articulated with respect to each other at a bending point (A), and the length (L) of the lever members (27) is greater than the axial range of movement of the bending point (A) with respect to the proximal support point (C) of the spring element (21) that articulates the spring element (21) to the first handle part (5).

13. The surgical instrument (1) according to claim 1, wherein the tool head (11) forms forceps, scissors, and / or gripping forceps.

14. The surgical instrument (1) according to claim 1, wherein the second handle element (7) is fixedly connected to or connectable to the shaft (9).

15. The surgical instrument (1) according to claim 1, wherein when the first tool component (5) abuts against the closed position in the absence of obstructing tissue (16), the first handle element (5) abuts against the closed position.

Images