Overload protection apparatus for a modular surgical instrument, and modular surgical instrument

Abstract

The present invention relates to an overload protection apparatus (1) for a modular surgical instrument system (100). The overload protection apparatus (1) has: handles (101, 101, 101"); shafts (102, 102', 102") having proximal end pieces (20, 20', 20"); and tool tips (103, 103', 103") for which different limit forces are predefined. The overload protection apparatus (1) has at least two force-limiting devices (K1, K2). Each tool tip (103, 103') is associated with one of the proximal end pieces (20, 20') which have cross-sectional profiles that differ in terms of their shape and / or their dimensions. Each force-limiting device (K1, K2) is designed to be selectively engaged with one of the proximal end pieces (20, 20') in a manner corresponding to their differing cross-sectional profiles so that the tool tip (103, 103') can be operatively connected, by the associated proximal end piece (20, 20'), to the one of the force-limiting devices (K1, K2) that is designed to limit the actuating force to the limit force predefined for said tool tip (103, 103').

Description

[0001] Overload protection device for a modular surgical instrument and modular instrument system

[0002] The invention relates to an overload protection device for limiting the force transmission in a modular surgical instrument. The invention further relates to a modular surgical instrument and a modular surgical instrument system comprising such an overload protection device.

[0003] It is known from the prior art that surgical instruments can be equipped with grasping and dissecting forceps, scissors, or other tools in which a tool part, usually the jaws of the aforementioned forceps and scissors, can be moved by manual force via a reciprocating actuating element. These surgical instruments comprise an elongated cylindrical shaft, with the tool and jaws located at its distal end and a handle at its proximal end. A rod-shaped actuating element is often used to actuate the jaws. This element extends through the shaft and is connected to the tool at its distal end.At the proximal end, the actuating element is operatively connected to the handle, so that moving a movable handle part relative to a fixed handle part causes an axial back and forth movement of the actuating element in the shaft and thus an opening and closing of the jaw parts.

[0004] The basic rule for all surgical instruments is that the material should not be stressed beyond its load limit by manual operation. With the miniaturization of jaws required for minimally invasive surgery, their load limit is reduced accordingly, and this limit should not be exceeded to avoid material fatigue and even material breakage. To prevent the surgeon from applying a closing force in practical use that exceeds the load limit of the jaws, surgical instruments can be equipped with a force limiter or overload protection that diverts any actuation force that exceeds the load limit to a housing component. In this way, material fatigue in the jaw area and even breakage of the jaws can be prevented. These must be avoided at all costs during surgery due to the potential damage to the tissue and organs in the surgical area.

[0005] WO 1999 / 004703 A1 discloses a device for limiting the force transmission from a movable actuating element to the jaws of a surgical instrument actuated thereby. The actuating element is assigned a wedge surface rising transversely to its direction of movement, with a housing that is spread by the wedge surface when the wedge surface is moved with the actuating element. The housing is circumferentially enclosed in the spreading area by an elastically expandable ring, so that the combination of the expandable housing and the elastic ring determines the force necessary to achieve any spreading at all. The force required for spreading is adjusted by design so that it corresponds to the maximum force to which the jaws are to be subjected.

[0006] The force limiter or overload protection is implemented via the handle and is specifically designed for the respective instrument, taking into account not only the specific load limit for the respective tool but also the leverage ratios present in the handle. Therefore, the use of a specific force limiter or overload protection in a modular surgical instrument system has not been possible to date, as there are no defined handle-tool combinations that allow for a force limiter in the handle adapted to a specific tool.

[0007] A modular surgical instrument system allows the user to individually configure their desired surgical instrument at any time. A modular system for surgical instruments can consist of two or three modular components, such as handles, outer shafts, and separate tool tips, as well as outer shafts with connected tool tips, from which two- or three-piece instruments can be assembled. The handles, outer shafts, and tool tips available in the modular system can differ in their areas of application and / or size.

[0008] One such modular surgical instrument system is known, for example, under the name Clickline® Instruments from the catalog “Highlights, Clickline® Instruments, Laparoscopic Hand Instruments, 01 / 2020” by Karl Storz SE & Co. KG, Tuttlingen, Germany. The system disclosed therein makes it possible to design a multitude of different surgical instruments from a combination of different handles, shafts, and tool tips. The handles have a mechanism that allows the handle to be separated from the shaft at the push of a button. Furthermore, the handles can have different handle designs and be equipped with, for example, catches, irrigation connections, and actuating elements for shaft rotation. For electrical high-frequency applications (generation of heat using high-frequency alternating current for removing or cutting tissue orFor use with vascular occlusion (hemostasis through vascular occlusion), the system includes insulated versions of handles and shafts, the handles also featuring a connection for a radiofrequency cable. The reusable two- or three-part design also allows for customized surgical instruments with different shaft lengths and diameters. In the event of damage, only the defective part needs to be replaced, and reusable components are autoclavable.

[0009] The overload protection currently available for such a modular instrument system, which is usually provided in the handles, is set to the same load value for all instrument inserts. This value is too high for sensitive tool tips whose limit force that can act on the sensitive tool tip is below the specified load value. Consequently, actuation forces that are below the specified load value but exceed the limit force of the sensitive tool tip cannot trigger the overload protection and thus cause damage to the sensitive tool tip. Conversely, there are more robust tool tips whose limit force lies above the specified load value, so that an increased actuation force is unnecessarily or undesirably limited to the specified load value by the overload protection.

[0010] Based on this prior art, it is the object of the present invention to provide a force limiting device, in other words an overload protection device or an overload safety device for a modular surgical instrument, which is adaptable to the limit forces predetermined for the different tool tips in order to reliably prevent damage to sensitive tool tips when actuating forces exceed the limit force, and to avoid unnecessary force limitation in the case of more robust tool tips.

[0011] This object is achieved by an overload protection device having the features of claim 1.

[0012] The further object of providing a modular surgical instrument system with an overload protection adaptable to the different tool tip types is achieved by the modular surgical instrument system with the features of independent claim 11.

[0013] The further object of providing a modular surgical instrument with an overload protection adapted to the selected tool tip is achieved by the modular surgical instrument with the features of independent claim 14.

[0014] Further developments / preferred embodiments are set out in the subclaims.

[0015] A first embodiment of an overload protection device according to the invention is intended for use in modular surgical instruments, each of which is modularly composed of a handle, a shaft defining a longitudinal axis A, and a tool tip, which can be selected from a modular surgical instrument system comprising different handles, different shafts with different proximal end pieces, and different tool tips. Optionally, the modular surgical instrument system can alternatively or additionally comprise preassembled tool tip-shaft combinations of the different tool tip and shaft types with the different proximal end pieces, so that a modular surgical instrument is composed of three or two parts.In both cases, the selected tool tip is arranged at a distal end of the shaft and can be actuated via an actuating element that is movable longitudinally axially within the shaft and can be operatively connected to the handle arranged at a proximal end of the shaft. According to the invention, the overload protection device is designed to be arranged in the handle and has at least two force-limiting devices designed to limit an actuating force to at least two of the limit forces predetermined for the tool tips.

[0016] In other words, the overload protection device is designed to limit an actuating force that can be transmitted from the actuating element to the tool tip to a limit force predetermined for the respective tool tip. A first limit force is predetermined at least for a first tool tip of the instrument system, and a second limit force that differs from the first limit force is predetermined for a second tool tip. Accordingly, further limit forces that differ from one another and from the first two limit forces can be predetermined for other tool tips of the instrument system. The overload protection device accordingly has at least two force-limiting devices, wherein a first force-limiting device is designed to limit the actuating force to the first limit force, and the second force-limiting device is designed to limit the actuating force to the second limit force.Analogously, the overload protection device can comprise additional force limiting devices designed to limit the actuation force to further predetermined limit forces. This creates an overload protection device dependent on the type of tool tip in a modular instrument system, with the overload protection device appropriate for the selected tool tip being activated in each modularly assembled instrument.

[0017] For this purpose, the overload protection device according to the invention provides a clear assignment of each force-limiting device to the respective tool tip by assigning each tool tip to one of the proximal end pieces, which have cross-sectional profiles that differ in terms of their shape and / or at least one dimension. This means that the cross-sectional profiles have different shapes or different dimensions, or both different shapes and different dimensions. Each force-limiting device is designed for selective engagement with one of the proximal end pieces corresponding to their different cross-sectional profiles. The proximal end piece can be a proximal end section of the shaft, or an intermediate piece or coupling element arranged at the proximal end of the shaft.In this way, the respective tool tip can be brought into operative connection by the associated proximal end piece with that of the force limiting devices which is designed to limit the actuating force to the limit force predetermined for the respective tool tip.

[0018] According to a preferred embodiment of the device according to the invention, the cross-sectional profiles of the proximal end pieces differ at least in terms of their diameter. The proximal end pieces, which can be distinguished due to their different diameters, essentially provide a coding assigned to the different tool tips, which enables selective engagement, i.e., selection and connection, with the appropriate force-limiting device that represents the overload protection appropriate for the tool tip.

[0019] If surgical instruments with high-frequency electrical applications can be assembled into the modular instrument system for which the overload protection device is intended, the components of the overload protection device may, where necessary, be made of an electrically insulating material, provided with an electrically insulating sheath or layer, or separated by an electrically insulating spacer.

[0020] According to a further embodiment of the overload protection device according to the invention, it has a force-limiting engagement for a different type of tool tip that does not require a limitation of the actuating force. For this purpose, the at least two force-limiting devices can be bypassed or engagement with each of the two force-limiting devices can be avoided by an additional proximal end piece assigned to the different type of tool tip that does not require a force-limiting engagement. For this purpose, the cross-sectional profile of the additional proximal end piece also differs in terms of its shape or in terms of at least one of its dimensions or in terms of its shape and at least one of its dimensions from the cross-sectional profiles of the proximal end pieces that are designed for selective engagement with the force-limiting devices.The additional proximal end piece can also be a proximal end section of the shaft, or an intermediate piece or coupling element arranged at the proximal end of the shaft. Preferably, the additional proximal end piece can also differ, at least in terms of diameter, from the proximal end pieces designed for selective engagement with the force-limiting devices, so that the coding by the additional end piece allows the force-limiting devices to be bypassed and allows force-free engagement for tool tips whose tool tip type does not require a limitation of the actuating force, for example, if the predetermined limit force exceeds the maximum actuating forces expected by average users.According to yet another embodiment of the overload protection device according to the invention, spring elements are provided as energy accumulators for the force-limiting devices. These spring elements can be pneumatic, hydraulic, or preferably simply helical spring elements. Each spring element can have one or more springs to provide a spring force tailored to the respective limit force. Each force-limiting device comprises a stop ring, a spring element, and a guide sleeve, which has a flange portion on the distal side and an annular inner stop on the proximal side around a passage opening for the proximal end pieces that are not assigned to the force-limiting device with the respective guide sleeve.The cross-section of the passage opening in the guide sleeve is smaller than the cross-sectional profile of the associated proximal end piece, so that the associated proximal end piece comes into contact with the annular inner stop and cannot pass through the passage opening. The spring element is arranged around the guide sleeve on the flange section, which in a standard load operating position, in which the actuating force is less than or equal to the corresponding limit force, rests against the respective stop ring. In an overload operating position, in which the actuating force is greater than the respective limit force, the flange section is spaced from the stop ring under the action of the respective proximal end piece on the annular inner stop.

[0021] In detail, a first force-limiting device thus comprises a first spring element as a force accumulator and further comprises a first stop ring, which is provided, for example, by an annular disk and allows the passage of all proximal end pieces, and a first guide sleeve. The first guide sleeve has, at one end of its cylindrical section - arranged on the distal side - a radially outwardly projecting first flange section and, at the other end of its cylindrical section - arranged on the proximal side - a radially inwardly projecting first annular inner stop around a first passage opening coaxial with the longitudinal axis A. This first passage opening has a diameter that is smaller than the diameter of the first proximal end piece and larger than the diameter of the second proximal end piece, so that each first proximal end piece rests against the first annular inner stop of the first guide sleeve around the first passage opening.

[0022] The same applies to cross-sections or cross-sectional dimensions of proximal end pieces with a non-circular cross-section. The first spring element is arranged around the first guide sleeve or its cylindrical section in order to press against the first flange section of the first guide sleeve. In this way, in a standard load operating position of the first force-limiting device, i.e., as long as the actuating force is less than or equal to the first limit force, the first flange section comes into contact with the first stop ring, which is arranged distally with respect to the first guide sleeve.In a first overload operating position of the overload protection device, in which the actuating force is greater than the first limit force, the first flange section is spaced from the first stop ring under the action of the first proximal end piece on the first annular inner stop and thus the first spring element is compressed against its spring force, corresponding to a force amount exceeding the first limit force.

[0023] The second force-limiting device is constructed analogously and accordingly comprises a second spring element as a force accumulator, a second stop ring, and a second guide sleeve. The second proximal end piece is provided for engagement with the second force-limiting device. Its diameter is not only smaller than the diameter of the first proximal end piece, but also smaller than the diameter of the first through-opening in the first guide sleeve, so that the second proximal end piece cannot engage with the first force-limiting device but can extend through the first through-opening in the first guide sleeve.The second guide sleeve has, at one end of its cylindrical section - arranged on the distal side - a radially outwardly projecting second flange section and, at the other end of its cylindrical section - arranged on the proximal side - a radially inwardly projecting second annular inner stop around a second passage opening coaxial with the longitudinal axis A. This second passage opening now has a diameter which is smaller than the diameter of the second proximal end piece, so that the second proximal end piece rests against the second annular inner stop of the second guide sleeve. Furthermore, the second spring element is arranged around the second guide sleeve and presses against the second flange section of the second guide sleeve, so that the second flange section is in a standard load operating position of the second force limiting device, ieas long as the actuating force is less than or equal to the second limit force, it rests against the second stop ring, which is arranged distally with respect to the second guide sleeve. In a second overload operating position of the overload protection device, i.e. when the actuating force is greater than the second limit force, the second flange section is spaced from the second stop ring under the action of the second proximal end piece on the second annular inner stop, and the second spring element is thus compressed against its spring force, corresponding to a force amount exceeding the second limit force. Here, too, the same applies with regard to the diameter for cross-sections or cross-sectional dimensions of proximal end pieces with a non-circular cross-section.According to a further embodiment of the overload protection device according to the invention, the stop rings can be fastened to an inner side of a housing component that is operatively connected to the at least two force-limiting devices and can be arranged in the handle or is part of the handle housing. The axial position of the stop rings determines a preload of the respective spring element in the standard load operating position, in which the respective spring element presses the respective flange section against the respective stop ring. The adaptation of the force-limiting devices to the respective limit forces is thus not limited to the selection of the spring elements depending on the spring constants, but can be adjusted by suitable preload using the stops.The housing component, which is directly or indirectly operatively connected to the at least two force-limiting devices for dissipating the force, can be formed as a single piece or in multiple pieces and arranged in certain or all handles of the modular surgical instrument system. With a direct operative connection, the force-limiting device rests directly on the housing component, whereas with an indirect operative connection, one force-limiting device rests on another force-limiting device, which rests on the housing component. The housing component can be manufactured separately from handle housing parts and firmly connected thereto; alternatively, at least one section or all sections of the housing component can be formed by parts of the handle housing, so that the housing component is integrated into the handle.

[0024] For the force-limiting intervention to bypass the force limiting devices when using a different type of tool tip for which a limit force is predetermined that does not require a limitation of a manual actuating force, a further embodiment of the overload protection device according to the invention provides that the housing component has a further annular inner stop around a further passage opening coaxial to the longitudinal axis A, which is provided for the passage of the actuating element and has a cross section that is smaller than the cross-sectional profile of the additional proximal end piece, which can thus abut the further annular inner stop on the housing component.Since the additional proximal end piece has a cross-section that is not only smaller than the cross-sectional profiles of the proximal end pieces assigned to the force-limiting devices, but also smaller than the cross-section of the through-openings in the guide sleeves, the additional proximal end piece cannot engage with the two force-limiting devices, but rather passes through the through-openings in the guide sleeves in order to come into contact with the third inner stop on the housing component without force limitation. As arrangement variants of the at least two force-limiting devices, according to still further embodiments of the overload protection device according to the invention, it is proposed that the at least two force-limiting devices are arranged longitudinally axially sequentially, i.e. one behind the other or following one another, or cascaded, i.e. nested step by step.In both cases, the at least two force limiting devices can preferably be arranged coaxially around the actuating element.

[0025] If the at least two force-limiting devices are arranged in a cascade according to a further embodiment of the overload protection device according to the invention, with a second force-limiting device partially surrounding a first force-limiting device, an inner diameter of the stop ring of the second force-limiting device and an inner diameter of the guide sleeve of the second force-limiting device are adapted to accommodate the spring element of the first force-limiting device. The spring element of the first force-limiting device extends through the stop ring of the second force-limiting device and into the guide sleeve of the second force-limiting device.The spring element of the first force limiting device is supported on the inner stop of the second force limiting device, wherein the spring element of the second force limiting device is supported on the further inner stop on the housing component.

[0026] In other words, according to this embodiment of the overload protection device according to the invention with the cascaded, i.e., nested, arrangement, two force-limiting devices can, for example, be arranged axially overlapping, so that the second force-limiting device partially surrounds the first force-limiting device. The second stop ring has a through-opening with a diameter adapted to an outer diameter of the first spring element. Thus, the first spring element, which presses against the first flange portion of the first guide sleeve, can extend through the through-opening of the second stop ring and into the second guide sleeve, which for this purpose has a corresponding diameter adapted to the outer diameter of the first spring element.The first spring element is supported on the proximal side against the second inner stop of the second guide sleeve, while the second spring element, which presses against the second flange section, is supported on the further inner stop on the housing component. The first force-limiting device is thus indirectly operatively connected to the housing element via the second force-limiting device. In this embodiment, the first force-limiting device is coupled to the second force-limiting device in such a way that the second force-limiting device protects the first force-limiting device from overload. The second force-limiting device can even be activated by the first force-limiting device if the first spring element is compressed to such an extent that the first guide sleeve comes to rest against the annular inner stop of the second guide sleeve.

[0027] According to a further embodiment of the overload protection device according to the invention, which is alternative to the above, in which the at least two force limiting devices are arranged longitudinally axially sequentially, the spring element of the first force limiting device is supported on the stop ring of the second force limiting device, and the spring element of the second force limiting device is supported on the further inner stop on the housing component.

[0028] In other words, according to this embodiment of the overload protection device according to the invention, for example, two force limiting devices can be arranged longitudinally axially sequentially, i.e. one behind the other. The first spring element, which presses distally against the first flange section of the first guide sleeve, can be supported proximally on the second stop ring, while the second spring element, which presses against the second flange section, is supported on the further inner stop on the housing component. Since the second stop ring belongs to the second force limiting device, the first force limiting device is also connected indirectly to the housing component via the second force limiting device, but without there being a coupling between the two force limiting devices, in which the second force limiting device can be activated to protect the first force limiting device from overload.

[0029] According to yet another embodiment of an overload protection device according to the invention, the first force-limiting device, which is designed to limit the actuating force to the first limit force, can be arranged on the distal side. The second force-limiting device, which is designed to limit the actuating force to the second limit force, which is greater than the first limit force, can then be arranged on the proximal side. This arrangement variant is intended in particular for cascaded force-limiting devices in order to protect the first force-limiting device, which is designed for the lower limit force, from overload. Of course, this arrangement variant can also be implemented with force-limiting devices arranged one behind the other along the longitudinal axis.

[0030] In a further embodiment of the overload protection device according to the invention, in which the overload protection device has at least three force-limiting devices, the cascaded and longitudinally sequential arrangement can be combined as described above. For example, the first force-limiting device can be cascaded with a third force-limiting device, and the third force-limiting device can be arranged one behind the other with the second force-limiting device, or conversely, the first force-limiting device can be arranged one behind the other with the third force-limiting device, and the third force-limiting device can be cascaded with the second force-limiting device. With more than three force-limiting devices, the arrangement variants can be combined accordingly.

[0031] Another subject matter of the invention is a modular surgical instrument system comprising different handles, different shafts with different proximal end pieces, and different tool tips. The different handles, shafts, and tool tips can be combined with one another to form a desired modular surgical instrument, in which the tool tip is arranged at a distal end of the shaft and can be actuated via an actuating element that is longitudinally movable in the shaft and operatively connected to the handle arranged at a proximal end of the shaft.In a first embodiment, the modular surgical instrument system according to the invention comprises an overload protection device according to the invention, so that for each surgical instrument composed of the modular surgical instrument system, an overload protection device adapted to the respective tool tip type is provided.

[0032] In further embodiments of the modular surgical instrument system according to the invention, the different shafts are provided with different proximal end pieces, each of which is assigned to one of the tool tips that differs with respect to the respective predetermined limit force. The overload protection device can be arranged in at least one of the handles, in particular in several handles, and preferably in all handles of the modular surgical instrument system. Furthermore, some of the tool tips with the respective actuating element, as well as shafts and handles of the modular surgical instrument system, can be designed for HF applications, which is why the overload protection device can be designed with electrically insulating components so that the overload protection device is equally suitable for use in both current-carrying and current-carrying modular surgical instruments.

[0033] Accordingly, in a first embodiment, a modular surgical instrument according to the invention comprises a handle, a shaft, and a tool tip, which are selected from a modular surgical instrument system according to the invention, which comprises different handles, different shafts with different proximal end pieces, and different tool tips. The tool tip is arranged at a distal end of the shaft and can be actuated via an actuating element that is longitudinally movable in the shaft and is operatively connected to the handle, which is arranged at a proximal end of the shaft.According to the invention, the modular surgical instrument system from which the modular surgical instrument is composed is a modular surgical instrument system according to the invention which has an overload protection device according to the invention, wherein the shaft selected for the modular surgical instrument has a proximal end piece associated with the selected tool tip in order to provide an operative connection with the overload protection device adapted to the predetermined limit force of the tool tip.

[0034] Further embodiments, as well as some of the advantages associated with these and other embodiments, will become clearer and more easily understood from the following detailed description with reference to the accompanying figures. Items or parts thereof that are substantially the same or similar may be provided with the same reference numerals. The figures are merely a schematic representation of one embodiment of the invention.

[0035] Showing:

[0036] Fig. 1 is a schematic, partially sectioned side view of a modular surgical instrument according to the invention with the modules handle, shaft with proximal end piece and tool tip,

[0037] Fig. 2 is a schematic side view of a modular surgical instrument system according to the invention,

[0038] Fig. 3 is a schematic representation of a modular surgical instrument system according to the invention with an example of a modular surgical instrument according to the invention that can be assembled therewith,

[0039] Fig. 4 is a schematic longitudinal sectional view through an overload protection device in an embodiment according to the invention,

[0040] Fig. 5 is a schematic longitudinal sectional view through an overload protection device in a further embodiment according to the invention,

[0041] Fig. 6 is a schematic longitudinal sectional view of the overload protection device of Fig. 4 in the normal load operating position in operative connection with a first proximal shaft end piece, Fig. 7 is a schematic longitudinal sectional view of the overload protection device of Fig. 6 in the first overload operating position in operative connection with the first proximal shaft end piece,

[0042] Fig. 8 is a schematic longitudinal sectional view of the overload protection device of Fig. 4 in normal load operating position in operative connection with a second proximal shaft end piece,

[0043] Fig. 9 is a schematic longitudinal sectional view of the overload protection device of Fig. 8 in the second overload operating position in operative connection with the second proximal shaft end piece,

[0044] Fig. 10 is a schematic longitudinal sectional view of the overload protection device of Fig. 4 in normal load operating position without force limitation in operative connection with a third proximal shaft end piece,

[0045] Fig. 11 is a schematic longitudinal sectional view of the overload protection device of Fig. 5 in normal load operating position without force limitation in operative connection with a third proximal shaft end piece,

[0046] Fig. 12 is a schematic longitudinal sectional view of the overload protection device of Fig. 5 in normal load operating position in operative connection with a first proximal shaft end piece,

[0047] Fig. 13 is a schematic longitudinal sectional view of the overload protection device of Fig.

[0048] 11 in the first overload operating position in operative connection with the first proximal shaft end piece,

[0049] Fig. 14 is a schematic longitudinal sectional view of the overload protection device of Fig. 5 in normal load operating position in operative connection with a second proximal shaft end piece,

[0050] Fig. 15 is a schematic longitudinal sectional view of the overload protection device of Fig. 13 in the second overload operating position in operative connection with the second proximal shaft end piece.

[0051] The invention relates to an overload protection device 1 for a modular surgical instrument 10, which is assembled from a modular surgical instrument system 100.

[0052] 4 to 15 show an overload protection device 1 according to the invention in different operating positions. A modular surgical instrument 10 assembled from a modular surgical instrument system 100 as indicated in Figs. 2 and 3 can be seen in Figs. 1 and 3. The overload protection device 1 is intended to prevent damage to (distal) parts of the tool tip 103 of a surgical instrument 10 that is assembled from a surgical instrument system 100. The overload protection provided by the overload protection device 1 is activated, for example, when the user operates the instrument 10 and the tool tip 103 orwhose jaw parts are blocked by gripping / cutting and, upon further actuation by the user, too much (manual) force is directed into the instrument 10: The overload protection device 1 absorbs the force component that exceeds a predetermined limit force for the tool tip 103, or a resulting (material) elongation of the instrument 10, and thus prevents failure of the instrument 10, for example due to damage or breakage of the tool tip 103.

[0053] Unlike the prior art, in which the force limitation or overload protection accommodated in the handle in the conventional modular surgical instrument system is set to the same (average) load value for all tool tips, which is suitable for moderately sensitive tool tips, the overload protection device 1 according to the invention not only enables the protection of moderately sensitive tool tips, but also the protection of more sensitive tool tips whose tolerable limit force is lower than the average load value, as well as the bypassing of the overload protection for more robust tool tips whose tolerable limit force significantly exceeds the average load value.

[0054] In a state-of-the-art modular surgical instrument system, an additional handle variant of each handle type would be required for each load case, with appropriate protective devices being used to avoid safety-critical combinations. Such a modular surgical instrument system would be excessively complex due to the significantly increased number of required handle variants, making it difficult for the user to select the modules for the desired instrument.

[0055] The overload protection device 1 according to the invention is designed as a multi-stage force limiting system having force limiting devices with different threshold levels, which are adapted to the limit forces predetermined for the respective tool tips or can be adapted by, for example, preloading spring elements as force accumulators to a defined threshold value.

[0056] As schematically indicated in Fig. 1 to 3, the overload protection device 1 according to the invention can be arranged in each handle 101, 102, 101", which can be assembled with a shaft 102, 102', 102" and a tool tip 103, 103', 103" to form a modular surgical instrument 10. For this purpose, the tool tip 103, 103', 103", which is provided here pre-assembled with the actuating element 21, is arranged at a distal end of the shaft 102, 102', 102", which defines a longitudinal axis A of the surgical instrument 10. The tool tip 103, 103', 103" can be actuated via the actuating element 21 which is movable longitudinally axially in the shaft 102, 102', 102". which is brought into operative connection with the handle 101, 10T, 101", which is arranged at a proximal end of the shaft 102, 102', 102". In the example shown, for example,The movement of the scissor-like handle parts of the handle 101, 102, 101" causes the actuating element 21 in the shaft 102, 102', 102", to be pushed back and forth, which is converted by means of a distal mechanism of the tool tip 103 into an opening and closing of the jaw parts of the tool tip 103, 103', 103". If an actuating force transmitted by the actuating element 21 exceeds the limit force predetermined, for example, for closing the jaw parts, if, for example, the jaw parts are already closed or otherwise blocked, the force component exceeding the limit force is transmitted via the distal mechanism to the shaft 102, 102', 102", which is connected at a proximal end piece 20, 20', 20" to the overload protection device 1 in the handle 101, 101', 101" in active compound.

[0057] The modular instrument 10 is assembled from a modular surgical instrument system 100, as shown in Figs. 2 and 3. The modular surgical instrument system 100, shown there in a simplified schematic, has three modular kits for the different handles 101, 101', 101" with actuating element 21, the different shafts 102, 102', 102" with the different proximal end pieces 20, 20', 20", and the different tool tips 103, 103', 103". Unlike what is shown in Fig. 2, the different shafts 102, 102', 102" can be combined in any way with the different proximal end pieces 20, 20', 20". This means that the selectable shafts 102, 102', 102" can differ not only in terms of their shaft type, but also in terms of the respective proximal end piece 20, 20', 20".The different handles 101, 101', 101" are each equipped with an overload protection device 1 according to the invention.

[0058] In the present context, the differentiation between the tool tips 103, 103', 103" is based on the limit force tolerable by the respective tool tip 103, 103', 103", i.e., a first limit force is predetermined for the first tool tips 103, a second limit force for the second tool tip 103', and a third limit force for the third tool tip 103". Nevertheless, the first tool tips 103 of a modular instrument system 100 - apart from the limit force - can certainly differ in function, material, and design. The same applies to the second and third tool tips 103', 103". Therefore, in a modular surgical instrument system 100, the number of tool tip variants, which can differ in function, material, and design, can deviate from the number of tool tip types defined with regard to the limit force and can even significantly exceed it.

[0059] The different proximal end pieces 20, 20', 20" allow an assignment to a specific tool tip 103, 103', 103" and, when mounting the shaft 102, 102', 102" on the handle 101, 10T, 101", enable an operative connection with the overload protection device 1 according to the invention by selective engagement with a force limiting device adapted to the predetermined limit force of the selected tool tip type (for sensitive and moderately sensitive tool tip types) or by bypassing these force limiting devices (for robust tool tip types).Since the different proximal end pieces 20, 20', 20" correlate with the different tool tips 103, 103', 103", each tool tip 103, 103', 103" is operatively connected to the overload protection device 1 via the associated proximal end piece 20, 20', 20" depending on its predetermined tolerable limit force in such a way that either the actuating force does not exceed the limit force predetermined for the sensitive or moderately sensitive tool tip 103, 103' or the actuating force is not limited for the robust tool tip 103".

[0060] The distinguishing parameter of the proximal end pieces 20, 20', 20" can, for example, be a cross-sectional dimension such as the diameter in the case of a circular cross-sectional profile of the proximal end piece 20, 20', 20" - otherwise, the proximal end pieces 20, 20', 20" of the same diameter can certainly differ in material and construction. In the case of a non-circular cross-sectional profile, the distinguishing parameter of the proximal end pieces 20, 20', 20" can be at least one suitable cross-sectional dimension such as a semi-axis in the case of an elliptical cross-section, a side length or diagonal in the case of a polygonal cross-section. Furthermore, the distinguishing parameter can be a shape of the cross-sectional profile (circular, elliptical, polygonal, etc.). Furthermore, the proximal end pieces 20, 20', 20" can have both different cross-sectional profiles and different cross-sectional dimensions as a combined distinguishing parameter.The proximal end piece 20, 20', 20" may simply be the proximal end portion of the shaft 102, 102', 102", or may be designed as an intermediate piece or coupling element that connects to the proximal end of the shaft 102, 102', 102".

[0061] Fig. 3 shows, by way of example, the assembly of a modular surgical instrument 10 comprising a first tool tip 103, a second shaft 102' with a first proximal end piece 20, which is assigned to the first tool tip 103, and a third handle 101" with the overload protection device 1 according to the invention, which has the force limiting devices K1, K2, indicated by the dashed borders. The first proximal end piece 20 is designed here, for example, to engage with the first force limiting device K1 in order to limit the actuating force to the limit force predetermined for the first tool tip 103. For this purpose, the first force limiting device K1 is designed for selective engagement with the proximal end piece 20 corresponding to its cross-sectional profile, which differs from the cross-sectional profiles of the proximal end pieces 20', 20" with regard to shape and / or dimensions.The cross-sectional profiles of the proximal end pieces 20', 20" not used in this example for assembling the surgical instrument 10 are designed, for example, for selective engagement with the second force limiting device K2, which limits the actuating force to the limit force predetermined for the second tool tip 103', or for bypassing the two force limiting devices K1, K2 if no limitation of the limit force is required for a different type of tool tip 103".

[0062] As an alternative to an instrument system 100 for such a three-part instrument 10, a two-part instrument (not shown) can be assembled from an alternative modular surgical instrument system having two kits: The first kit comprises the different handles 101 with the overload protection device 1 according to the invention, while the second kit provides differently combined modules from the different tool tips 103, 103', 103" and the different shafts 102, 102', 102" with the proximal end pieces 20, 20', 20" assigned to the respective tool tip 103, 103', 103".Furthermore, a modular surgical instrument system 100 according to the invention can also combine the two-part and three-part variants and have four modules: different handles with overload protection devices, different shafts with different proximal end pieces, different tool tips and the differently combined modules of tool tips and shafts with the appropriately assigned proximal end pieces.

[0063] Of course, a modular surgical instrument system 100 according to the invention is not limited to three types per kit; the individual kits for handles, shafts with proximal end pieces, and tool tips can also have more or fewer than three types each. The number of variants of the proximal end pieces, due to the assignment to the different tool tips, corresponds to the number of variants of the tool tips, which are determined according to the different tolerable limit forces. Furthermore, the number of variants of the types in the respective kits does not have to be the same: For example, the number of different handles can be significantly greater than the number of different shafts, etc.

[0064] The overload protection device 1 according to the invention is shown in a first embodiment with cascaded force limiting devices K1, K2 in Fig. 4 and in Figs. 6 to 10 in different application variants and operating positions. An alternative embodiment with force limiting devices K1, K2 arranged one behind the other in the longitudinal axial direction can be seen in Fig. 5 and in Figs. 11 to 15 in different application variants and operating positions. For simplification, the proximal end piece 20, 20', 20" in the figures is designed with a uniform diameter throughout, whereas in the implementation only an area required for engagement needs to be adapted accordingly. The shaft 102, 102', 102" with the end piece 20, 20', 20" can therefore also be designed with graduations.

[0065] The overload protection device 1 in both embodiments is designed to selectively limit or permit an actuating force that can be transmitted from the actuating element 21 (shown in Fig. 4) to the respective tool tip 103, 103', 103" to the limit force predetermined for the respective tool tips 103, 103', 103". In the examples shown in Figs. 4 to 15, the overload protection device 1 has two force-limiting devices K1, K2. Of course, overload protection devices 1 according to the invention can also have more than two force-limiting devices K1, K2, wherein the arrangement, structure and functioning of a third or each further force-limiting device can readily be derived from the arrangement, structure and functioning of the described first and second force-limiting devices K1, K2.Of these two, the first force-limiting device K1 is designed to limit the actuating force to a first limit force predetermined for a first tool tip 103, and the second force-limiting device K2 is designed to limit the actuating force to a second limit force predetermined for a second tool tip 103'. Furthermore, the overload protection device 1 provides a force-limitless engagement for a third tool tip 103', whose tolerable limit force is greater than an actuating force that can be applied by the user, so that a force limitation is not required and may even be undesirable.

[0066] The unambiguous assignment of the two force limiting devices K1, K2 to the respective first and second tool tips 103, 103' is effected via the distinguishable proximal end pieces 20, 20' of a tool shaft 102, 102', 102", at the distal end of which the respective tool tip 103, 103' is arranged. For this purpose, the first proximal end piece 20 is designed to engage with the first force limiting device K1, and correspondingly, the second proximal end piece 20' is designed to engage with the second force limiting device K2. The assignment of the third tool tip 103" to the force-limitless engagement of the overload protection device 1, wherein the two force limiting devices K1, K2 are bypassed, is correspondingly provided by a third proximal end piece 20", which differs from the first and second proximal end pieces 20, 20'.For example, the first, second and third proximal end pieces 20, 20', 20" may differ in terms of diameter d1, d2, d3.

[0067] In the illustrated examples, a first proximal end portion 20 with a largest diameter d1 is provided for engagement with the first force-limiting device K1 in order to limit an actuating force applied to a first tool tip 103 via the actuating element 21 to a first limit force predetermined therefor. A second proximal end portion 20' with a mean diameter d2 is provided for engagement with the second force-limiting device K2 in order to limit an actuating force applied to a second tool tip 103 via the actuating element 21 to a second limit force predetermined therefor.In the illustrated examples, the first force-limiting device K1 for limiting the actuating force to the first limit force is arranged distally with respect to the second force-limiting device K2, which limits the actuating force to the second limit force, which in this case is greater than the first limit force. The third proximal end section 20" with a smallest diameter d3 is provided to bypass the two force-limiting devices K1, K2 in order not to limit the actuating force applied to a third tool tip 103 via the actuating element 21. The third proximal end section 20" with the smallest diameter d3 can be supported on a housing component 8 of the overload protection device 1, which can be arranged in the handle 101 or is an integral part of a handle housing.This housing component 8 is further operatively connected to the force limiting devices K1, K2 in that the second force limiting device K2 is supported on the housing component 8, while the first force limiting device K1 is supported by the second force limiting device K2.

[0068] Here, the first force-limiting device K1 has a first spring element 4, for example a hydraulic, pneumatic, or helical compression spring, as an energy accumulator. Coil spring elements may be preferred due to their simple and economical implementation. However, an overload protection device according to the invention can also have pneumatic or hydraulic spring elements as energy accumulators, each formed by one or more air or fluid chambers. Furthermore, the first force-limiting device K1 has a first guide sleeve 3 with a cylinder section 3.0, which has an (inner) diameter adapted to the (outer) diameter d1 of the first proximal end piece 20, so that the respective first proximal end piece 20 is received in the first guide sleeve 3. At a distal end of the cylinder section 3.0, the first guide sleeve 3 has a first, radially outwardly projecting flange section 3.2.At the other, proximal end of its cylinder section 3.0, the first guide sleeve 3 has a first annular inner stop S1. This is designed to project radially inward around a first through-opening 3.1 coaxial with the longitudinal axis A, which has a diameter that is smaller than the diameter d1 but larger than the diameter d2 of a second proximal end piece 20. Therefore, a second proximal end piece 20' can pass through the first through-opening 3.1 of the first guide sleeve 3, while a first proximal end piece 20 comes into contact with the first annular inner stop S1. By contacting the first proximal end piece 20 (with diameter d1) with the first annular inner stop S1 of the first guide sleeve 3, the operative connection is established with the first force-limiting device K1, which provides the adapted limitation of the actuating force to the first limit force.For this purpose, the first spring element 4 is arranged around the cylinder section 3.0 of the first guide sleeve 3 and presses distally against the first flange section 3.2 of the first guide sleeve 3.

[0069] Without external force applied via a shaft 102, 102', 102" or the first proximal end piece 20, the first flange section 3.2 rests against a first stop ring 2 due to the action of the first spring element 3. The first stop ring 2 is fastened in the housing component 8 as a further part of the first force-limiting device K1 and, on the proximal side, provides the stop ring surface for the first flange section 3.2 around a passage opening 2.1 coaxial with the longitudinal axis A. The passage opening 2.1 has a diameter that is larger than the diameter d1 of the first proximal end piece 20, but smaller than an outer diameter of the flange section 3.2 of the first guide sleeve 3.

[0070] The second force-limiting device K2 is constructed analogously and has a second spring element 7 as an energy accumulator, for example also a hydraulic, pneumatic, or preferably helical compression spring, and a second guide sleeve 6 with a cylinder section 6.0 whose (inner) diameter is larger than the (outer) diameter d2 of a second proximal end piece 20', so that a second proximal end piece 20 is received in the second guide sleeve 6. At a distal end of the cylinder section 6.0, the second guide sleeve 6 has a second, radially outwardly projecting flange section 6.2. At the other, proximal end of its cylinder section 6.0, the second guide sleeve 6 has a second annular inner stop S2. This inner stop projects radially inward around a second through-opening 6 coaxial with the longitudinal axis A.1, which has a diameter that is smaller than the diameter d2, but larger than the diameter d3 of a third proximal end piece 20". Therefore, a third proximal end piece 20" can pass through the second passage opening 6.1 of the second guide sleeve 6, while a second proximal end piece 20' comes into contact with the second annular inner stop S2. By the second proximal end piece 20' (with diameter d2) coming into contact with the second annular inner stop S2 of the second guide sleeve 6, the operative connection is established with the second force limiting device K2, which provides the adapted limitation of the actuating force to the second limit force. For this purpose, the second spring element 7 is arranged around the cylinder section 6.0 of the second guide sleeve 6 and presses on the distal side against the second flange section 6.2 of the second guide sleeve 6.

[0071] Without external force acting via the shaft 102, 102', 102" or the second proximal end piece 20', the second flange section 6.2 rests against a second stop ring 5 due to the action of the second spring element 7. The second stop ring 5 is fastened in the housing component 8 as a further part of the second force-limiting device K2 and provides a stop ring surface on the proximal side around a passage opening 5.1 for the second flange section 6.2 that is coaxial with the longitudinal axis A. The passage opening 5.1 has a diameter that is larger than the diameter d2 of the second proximal end piece 20, but smaller than an outer diameter of the flange section 6.2 of the second guide sleeve 6.

[0072] In addition to the selection of the spring constant of the respective spring element 4, 7, the force limiting devices K1, K2 can be adapted to the respective predetermined limit forces of the first and second tool tips 103, 103' by adjusting the preload of the respective spring element 4, 7 in the standard load operating position without the application of force via the shaft 102, 102', 102". This can be achieved by the respective axial positioning of the respective stop ring 2, 5, against which the respective spring element 4, 7 presses via the respective flange section 3.2, 6.2, on the inside of the housing component 8. For this purpose, the housing component 8 can, for example, have an internal thread 8.2 in a cylindrical section and the two annular stops 2, 5 a corresponding external thread, so that the stops 2, 5 can be axially positioned and fixed in the axial direction by screwing in.The spring elements 4, 7, thus preloaded via the respective distal stop ring, are activated from the set preload force. If the actuating force is below the spring force set by the preload, the overload limitation remains ineffective. To provide the force-limiting engagement, the use of third proximal end pieces 20" is provided, which have a diameter d3 that is smaller than the diameters d1, d2 of the first and second proximal end sections 20, 20', so that a third proximal end piece 20" does not engage with either of the two force-limiting devices K1, K2. For a third proximal end piece 20", the overload protection device 1 has a third annular inner stop S3, which is present on the housing component 8 around a third passage opening 8.1 coaxial with the longitudinal axis A. The third passage opening 8.1, which is provided for the passage of the actuating element 21, has a diameter which is smaller than the diameter d3 of a third proximal end piece 20", which consequently comes to bear against the third annular inner stop S3 of the housing component 8.

[0073] Furthermore, the second spring element 7 of the second force-limiting device K2 is supported on the third inner stop S3 of the housing component 8 and presses against the second flange section 6.2. The first spring element 7 extends axially beyond the proximal end of the second guide sleeve 6 with the second annular inner stop S2, so that the proximal end of the second guide sleeve 6 with the second annular inner stop S2 is spaced from the third annular inner stop S3 on the housing component 8. This distance is available to the second force-limiting device K2 as spring travel b2 (cf. Fig. 6, 12) and is designed to be adapted to predeterminable parameters. The parameters are, for example, the second limit force, the spring constant of the second spring element 7 and its preload.

[0074] In the examples shown in the figures, the housing component 8 is depicted as a single-piece cylindrical sleeve, which is delimited at one end by the radially inwardly projecting annular inner stop S3. Contrary to what is depicted, a housing component of an overload protection device 1 according to the invention can also be multi-part and have various housing sections, which, for example, can also include sections of the handle 101, 101', 101", which can engage with the various components of the overload protection device 1 according to the invention (stops 2, 5, second spring element 7, optionally third proximal end piece 20").

[0075] The differences between the alternative embodiments of an overload protection device 1 according to the invention shown in Fig. 4 and 5 lie in the arrangement of the force limiting devices K1, K2 in relation to one another. In the cascaded arrangement from Fig. 4 (as well as Figs. 6 to 10), the two force limiting devices K1, K2 are nested within one another, arranged to overlap axially, so that the second force limiting device K2 partially surrounds the first force limiting device K1. For this purpose, the diameter of the passage opening 5.1 of the second stop ring 5 as well as the diameter of the cylinder section 6.0 of the second guide sleeve 6 are adapted to an outer diameter of the first spring element 4, which extends through the passage opening 5.1 of the second stop ring 5 and into the second guide sleeve 6.Thus, not only the second proximal end piece 20' with average diameter d2 is received in the second guide sleeve 6, but also the first spring element 3, which is arranged around the cylinder section 3.0 of the first guide sleeve 3. The first spring element 3 extends axially beyond the end of the first guide sleeve 3 with the annular inner stop S1 and is supported on the annular inner stop S2 of the second guide sleeve 6, so that the proximal end of the first guide sleeve 3 with the annular inner stop S1 is spaced from the second annular inner stop S2.

[0076] In the longitudinally axially successive arrangement in Fig. 5 (as well as Figs. 11 to 15), the force limiting devices K1, K2 are arranged axially one behind the other, wherein the first spring element 4, which presses distally against the first flange section 3.2 of the first guide sleeve 3, is supported on the second stop ring 5, which is fastened in the housing component 8. Here, too, the first spring element 4 extends axially beyond the end of the first guide sleeve 3 with the annular inner stop S1, so that the proximal end of the first guide sleeve 3 with the annular inner stop S1 is spaced from the second stop ring 5.

[0077] This distance between the proximal end of the first guide sleeve 3 with the annular inner stop S1 and the second annular inner stop S2 (in the cascaded arrangement) or the second stop ring 5 (in the longitudinally axially successive arrangement) is available to the first force-limiting device K1 as spring travel b1 (see Figs. 6, 12) and is designed to match predeterminable parameters. The parameters include, for example, the first limit force, the spring constant of the first spring element 4, and its preload.

[0078] When designing the force limiting devices K1, K2 with the spring elements 4, 7, the entire working range of the tool tips used can be taken into account with regard to the spring travel b1, b2. Once the first guide sleeve 3 has covered the spring travel b1 in the first overload operating position (Fig. 7 or Fig. 13), it strikes the second annular inner stop S2 of the second guide sleeve 6 or the second distal stop ring 5. This forms the mechanical overload stop for the first force limiting device K1 and thus prevents compression of the first spring element 4 in an unwanted / undefined range or ensures a defined end point for this overload level. In the cascaded arrangement (Fig.7), the next overload stage, i.e., the second force-limiting device K2, can be activated from the moment the first guide sleeve 3 abuts the second annular inner stop S2 of the second guide sleeve 6, provided the gradation of the spring forces is appropriately selected / adjusted. In the axially successive arrangement (Fig. 13), in which the first spring element 4 is mounted on the second stop ring against the housing element 8, there is no effect on the subsequent stage or force-limiting device K2, which is activated only by using a second proximal end piece 20'.

[0079] Since in the cascaded arrangement the first spring element 3 is supported on the second annular inner stop S2 of the second guide sleeve 6, which is spring-mounted above its flange section 6.2, against which the second spring element 7 rests, the second spring element 7 must have a higher spring constant than the first spring element 4, since otherwise the first force-limiting device K1 cannot act independently of the second force-limiting device K2. The corresponding assignments of first and second tool tips 103, 103', first and second proximal end sections 20, 20' and first and second force-limiting devices K1, K2 ensure that the second limit force to which the actuating force is limited by the second force-limiting device K2 is greater than the first limit force to which the actuating force is limited by the first force-limiting device K1.In the longitudinally axially successive arrangement, however, the force limiting devices K1, K2 can act independently, so that, unlike in the cascaded arrangement, the second spring element 7 does not necessarily have to have a higher spring constant than the first spring element 4. In this case, too, it can be preferred that, due to the corresponding assignments of first and second tool tips 103, 103', first and second proximal end sections 20, 20' and first and second force limiting devices K1, K2, the second limit force to which the actuating force is limited by the second force limiting device K2 is greater than the first limit force to which the actuating force is limited by the first force limiting device K1.However, in the case of the longitudinally axially successive arrangement, it is also possible that, conversely, by a correspondingly alternative assignment of first and second tool tips 103, 103', first and second proximal end sections 20, 20', and first and second force-limiting devices K1, K2, the second limit force to which the actuating force is limited by the second force-limiting device K2 is smaller than the first limit force to which the actuating force is limited by the first force-limiting device K1. Depending on the design of the limitation, the various spring elements or force-limiting devices in the cascaded arrangement can thus be coupled in series, or each spring element or force-storage arrangement can be arranged as a separate package.The spring elements are each pre-tensioned to a defined threshold value, so that when a delicate tool tip with a low limit load is inserted, a coupling is created with a weak spring element, which creates a low threshold level for the overload protection device. If, on the other hand, a tool tip is inserted that requires a higher threshold level, a coupling is created with a stronger spring element of the overload protection device. A stronger spring element for a higher actuation force can, if required, be formed by several springs arranged in parallel. The weaker spring element of the overload protection device is not loaded and therefore remains ineffective, whereby the weaker spring element must always be arranged in such a way that it cannot be destroyed by the higher load. This is achieved in the cascaded arrangement by placing the weaker spring element in front of the stronger spring element.is supported on it and is independently provided with the mechanical stop ring, which protects the spring element from permanent (plastic) change outside the intended working range.

[0080] The alternative arrangement variants of the force limiting devices result in a certain degree of freedom in terms of structural design. The overload protection device can be designed with the spring elements either axially one behind the other or cascaded into one another, resulting in a compact design or, if necessary, a design that can be specifically adapted to the available installation space in the handle. If the overload protection device has more than two force limiting devices, combinations of both arrangement variants are also conceivable. With three force limiting devices, the first and a third force limiting device can be arranged in a cascade as described above, with the spring element of the third force limiting device being supported not on the housing element but on the stop ring of the second force limiting device, so that the third and second force limiting devices form an axially sequential arrangement as described above.Conversely, it is also conceivable for the first force-limiting device to be arranged longitudinally axially one behind the other with the third force-limiting device, wherein the spring element of the third force-limiting device is supported not on the housing element, but on the annular inner stop of the guide sleeve of the second force-limiting device when the third and second force-limiting devices are arranged in cascade. The third force-limiting device is thus part of both arrangement variants. Modifications of the overload protection device according to the invention for use in electrical high-frequency applications (HF applications) are not shown. The components of the overload protection device 1 can, where necessary, consist of an electrically insulating material, be provided with an electrically insulating sheath or layer, or be separated by an electrically insulating intermediate piece.If the current is transmitted to the tool tip, for example, through the actuating element, which extends through the shaft and the proximal end piece, the shaft and its proximal end piece, as well as the housing component at the opening for the actuating element, can be designed to be electrically insulating. This insulation can be advantageously achieved with comparatively little technical effort, for example, using an insulating sleeve.

[0081] Different application variants and operating positions of the overload protection device 1 according to the invention are explained with reference to Figs. 6 to 10 for the overload protection device 1 according to the invention from Fig. 4 with cascaded force limiting devices K1, K2 and with reference to Figs. 11 to 15 for the overload protection device 1 according to the invention from Fig. 5 with force limiting devices K1, K2 arranged one behind the other in the longitudinal axial direction.

[0082] Fig. 6, 7 and 12, 13 each show the use of the respective overload protection device 1 with a first proximal end piece 20 with the largest diameter d1, which is assigned to the first tool tips 103 with a lowest tolerable limit force. The first tool tip 103 is brought into operative connection with the first force limiting device K1 via the first proximal end section 20, in that the first proximal end piece 20 extends into the first guide sleeve 3 and comes into contact with the first annular inner stop S1 of the first guide sleeve 3. In the standard load operating position shown in Fig. 6 and 12, in which the actuating force is less than or equal to the first limit force, the first flange section 3.2 rests against the first stop ring 2. Fig.7 and 13 show the first overload operating position of the overload protection device 1 according to the invention, in which the actuating force is greater than the limit force predetermined for the first tool tips. The actuating force is transmitted via the respective shaft 102, 102', 102" with the first proximal end section 20 to the first annular inner stop S1 of the first guide sleeve 3. And via the first flange section 3.2 of the first guide sleeve 3, the force is introduced into the first spring element 4, which is axially compressed, so that the guide sleeve 3 is moved axially in the proximal direction and the first flange section 3.2 is spaced from the first stop ring 2 by a first displacement path x1. The length of the first displacement path x1 depends on the applied actuating force and, with a suitable design of the force-limiting device K1, is less than the first spring displacement b1.

[0083] Analogously, Fig. 8, 9 and 14, 15 show the normal load operating position and the second overload operating position of the respective overload protection device 1 with a second proximal end piece 20 with the average diameter d2, which is assigned to the second tool tips 103' with a medium tolerable limit force. In this case, a second tool tip 103' is brought into operative connection with the second force limiting device K2 via the second proximal end section 20' of a shaft 102, 102', 102". For this purpose, the second proximal end piece 20' with the average diameter d2 extends through the first guide sleeve 3 and its through-opening 3.1 into the second guide sleeve 6. There, the second proximal end piece 20 comes to rest against the second annular inner stop S2 of the second guide sleeve 6.

[0084] In the standard load operating position shown in Figs. 8 and 14, in which the actuating force is less than or equal to the tolerable limit force of the second tool tips 103', the second flange section 6.2 rests against the second stop ring 5. Figs. 9 and 15 show the second overload operating position of the overload protection device 1 according to the invention, in which the actuating force is greater than the limit force predetermined for the second tool tips 103'. The actuating force is transmitted via the shaft 102, 102', 102" with the second proximal end piece 20' to the second annular inner stop S2 of the second guide sleeve 6. And via the second flange section 6.2 of the second guide sleeve 6, the force is introduced into the second spring element 7, which is axially compressed, so that the second guide sleeve 6 is moved axially in the proximal direction and the second flange section 6.2 is spaced from the second stop ring 2 by a second displacement distance x2. The length of the second displacement distance x2 depends on the applied actuating force and, with a suitable design of the force-limiting device K2, is smaller than the second spring travel b2.

[0085] 10 and 11 show the respective overload protection device 1 according to the invention in use without force limitation, wherein the two force limiting devices K1, K2 are bypassed or deactivated. This is achieved by a third proximal end piece 20" with the smallest diameter d3, which is assigned to the tool tips 103" with a tolerable limit force that is not exceeded by the actuating forces that can be applied by an average user. The third proximal end piece 20" with the smallest diameter d3 extends through the first guide sleeve 3 and its through-opening 3.1 as well as through the second guide sleeve 6 and its through-opening 6.1 up to the third annular inner stop S3 on the housing component 8. The actuating force is not limited by the force limiting devices K1, K2.

[0086] The assignment of tool tips, which differ in terms of the tolerable force limit, to the different proximal end pieces of the shafts, which provide selective engagement with the appropriate force-limiting device or with the housing, represents a type of coding that allows safety-critical combinations to be provided and assigned to a specific threshold level. In practical use, this means increased convenience for the user. Because the modular system does not provide any unsuitable or critical combinations, module selection requires no additional attention from the user, as the correct overload protection is automatically selected via the interface coding, i.e., assignment of the tool tip to the appropriate force-limiting device or its bypassing via the proximal end piece.

[0087] In the present examples, the diameter of the proximal end pieces 20, 20', 20" is used as the distinguishing parameter that provides the appropriate assignment of tool tip and force-limiting device, thus allowing a simple coaxial arrangement of the force-limiting devices K1, K2. However, diameter should also be understood here as a profile dimension of a proximal end piece with a cross-sectional geometry that deviates from a circular shape. In order to increase the distinguishability of the proximal end pieces, the proximal end pieces can, for example, have different cross-sectional profiles - in addition to different colors, for example. In this case, the respective guide sleeves can be designed with a correspondingly adapted inner profile.

[0088] The drawings, the description, and the claims contain numerous features in combination. It is understood that the aforementioned features can be used not only in the respective combination specified, but also in other combinations or alone, without departing from the scope of the present invention. The present invention provides an overload protection device 1 for a modular surgical instrument system 100, a modular surgical instrument system 100, and a modular surgical instrument 10 with the overload protection device 1. The overload protection device 1 has handles 101, 10T, 101", shafts 102, 102', 102" with proximal end pieces 20, 20', 20", and tool tips 103, 103', 103", for which different limit forces are predetermined, for assembling a modular surgical instrument 10.The overload protection device 1 is designed for arrangement in the handle 101, 10T, 101' and has at least two force limiting devices K1, K2, which are designed to limit an actuating force to at least two of the limit forces predetermined for the tool tips 103, 103'. Each tool tip 103, 103' is assigned one of the proximal end pieces 20, 20', which have cross-sectional profiles that differ in terms of their shape and / or dimensions.Each force limiting device K1, K2 is designed for selective engagement with one of the proximal end pieces 20, 20' corresponding to their differing cross-sectional profiles, so that the respective tool tip 103, 103' can be brought into operative connection by the associated proximal end piece 20, 20' with that of the force limiting devices K1, K2 which is designed to limit the actuating force to the limit force predetermined for the respective tool tip 103, 103'.

[0089] LIST OF REFERENCE SYMBOLS

[0090] 1 overload protection device

[0091] 2 First stop ring

[0092] 2.1 Passage opening

[0093] 3 First guide sleeve

[0094] 3.0 Cylinder section

[0095] 3.1 Passage opening

[0096] 3.2 Flange section

[0097] 4 First spring element

[0098] 5 Second stop ring

[0099] 5.1 Passage opening

[0100] 6 Second guide sleeve

[0101] 6.0 Cylinder section

[0102] 6.1 Passage opening

[0103] 6.2 Flange section

[0104] 7 Second spring element

[0105] 8 Housing component

[0106] 8.1 Passage opening

[0107] 8.2 Thread

[0108] 20, 20', 20" Proximal end piece

[0109] 21 Actuating element

[0110] 10 Surgical instrument

[0111] 100 Modular Surgical Instrument System

[0112] 101, 10T, 101" handle

[0113] 102, 102', 102" shaft

[0114] 103, 103', 103“ Tool tip A Instrument longitudinal axis

[0115] K1 , K2 First, second force limiting device

[0116] S1 , S2, S3 First, second, third inner stop b1, b2 First, second spring travel d1, d2, d3 Diameter of proximal end piece (20) of the first, second, third

[0117] End type x1 , x2 First, second displacement path

Claims

PATENT CLAIMS 1. Overload protection device (1) for a modular surgical instrument system (100) comprising different handles (101, 102, 102', 102"), different shafts (102, 102', 102") with different proximal end pieces (20, 20', 20") and different tool tips (103, 103', 103"), for which different limit forces are predetermined, from which a modular surgical instrument (10) can be assembled, in which the tool tip (103, 103', 103") is arranged at a distal end of the shaft (102, 102', 102"), which defines a longitudinal axis (A), and is connected to an actuating element (21) which is movable longitudinally axially in the shaft (102, 102', 102") and which is connected to the handle (101, 10T, 101"), which is arranged at a proximal end of the shaft (102, 102', 102"), is in operative connection, characterized in that the overload protection device (1) is designed to be arranged in the handle (101, 10T, 101") and at least two force limiting devices (K1,K2) which are designed to limit an actuating force to at least two of the limit forces predetermined for the tool tips (103, 103'), wherein each tool tip (103, 103') is assigned one of the proximal end pieces (20, 20') which have cross-sectional profiles which differ in terms of their shape or in terms of at least one of their dimensions or in terms of their shape and at least one of their dimensions, and wherein each force-limiting device (K1, K2) is designed for selective engagement with one of the proximal end pieces (20, 20') corresponding to their differing cross-sectional profiles, so that the respective tool tip (103, 103') can be brought into operative connection by the assigned proximal end piece (20, 20') with that of the force-limiting devices (K1, K2) which are designed to limit the actuating force to the limit forces predetermined for the respective tool tip (103,103') predetermined limit force., 2. Overload protection device (1) according to claim 1, characterized in that the cross-sectional profiles of the proximal end pieces (20, 20') differ with regard to their diameters (d1, d2). Overload protection device (1) according to claim 1 or 2, characterized in that the overload protection device (1) provides a force-limiting engagement for a different type of tool tip (103") for which no limit force is predetermined, wherein the at least two force-limiting devices (K1, K2) can be bypassed by an additional proximal end piece (20"), the cross-sectional profile of which differs in terms of its shape or in terms of at least one of its dimensions or in terms of its shape and at least one of its dimensions from the cross-sectional profiles of the proximal end pieces (20, 20') which are designed for selective engagement with the force-limiting devices (K1, K2), wherein the additional proximal end piece (20") preferably differs at least in terms of the diameter (d3) from the proximal end pieces (20, 20') which are designed for selective engagement with the force-limiting devices (K1, K2).Overload protection device (1) according to at least one of claims 1 to 3, characterized in that each force limiting device (K1, K2) has a stop ring (2, 5), a spring element (4, 7) and a guide sleeve (3, 6), which has a flange section (3.2, 6.2) on the distal side and an annular inner stop (S1, S2) on the proximal side around a passage opening (3.1, 6.1), the cross section of which is smaller than the cross-sectional profile of the associated proximal end piece (20, 20'), so that the respective proximal end piece (20, 20') can be brought into contact with the annular inner stop (S1, S2), and wherein the spring element (4, 7) is arranged around the guide sleeve (3, 6) on the flange section (3.2, 6.2) is arranged, which in a standard load operating position in which the actuating force is less than or equal to the corresponding limit force, rests against the respective stop ring (2, 5) and in an overload operating position in which the actuating force is greater than the respective limit force, can be spaced apart from the stop ring (2, 5) under the action of the respective proximal end piece (20, 20') on the annular inner stop (S1, S2). Overload protection device (1) according to claim 4, characterized in that each stop ring (2, 5) is fastened to an inner side of a housing component (8) which is operatively connected to the at least two force-limiting devices (K1, K2) and can be arranged in the handle (101, 10T, 101"), wherein a preload of the respective spring element (4, 7) in the standard load operating position can be determined by an axial positioning of the respective stop ring (2, 5). Overload protection device (1) according to claim 5, characterized in that the housing component (8) has a further annular inner stop (S3) around a further passage opening (8) provided for the actuating element (21).1) whose cross-section is smaller than the cross-sectional profile of the additional proximal end piece (20") assigned to the different tool tip (103"), so that the additional proximal end piece (20") can be brought into contact with the further annular inner stop (S3) of the housing component (8).Overload protection device (1) according to claim 5 or 6, characterized in that the at least two force limiting devices (K1, K2) are arranged in a cascade, wherein a first force limiting device (K1) partially surrounds a second force limiting device (K2), and an inner diameter of the stop ring (5) and the guide sleeve (6) of the second force limiting device (K2) is designed to accommodate the spring element (4) of the first force limiting device (K1), wherein the spring element (4) of the first force limiting device (K1) extends through the stop ring (5) and into the guide sleeve (6) of the second force limiting device (K2) and is supported on the inner stop (S2) of the second force limiting device (K2), and wherein the spring element (7) of the second force limiting device (K2) is supported on the further inner stop (S3) of the housing component (8). Overload protection device (1) according to claim 5 or 6, characterized in that the at least two force-limiting devices (K1, K2) are arranged sequentially along the longitudinal axis, wherein the spring element (4) of a first force-limiting device (K1) is supported on the stop ring (5) of a second force-limiting device (K2), and wherein the spring element (7) of the second force-limiting device (K2) is supported on the further inner stop (S3) of the housing component (8). Overload protection device (1) according to claim 7 or 8, characterized in that the first force-limiting device (K1), which is designed to limit the actuating force to the first limit force, is arranged on the distal side, and the second force-limiting device (K2), which is designed to limit the actuating force to the second limit force, which is greater than the first limit force, is arranged on the proximal side.Overload protection device (1) according to claims 7 and 8, characterized in that the overload protection device (1) has at least three force limiting devices (K1, K2) in a combined cascaded and a longitudinally axial sequential arrangement, wherein the first force limiting device (K1) is cascaded with a third force limiting device and the third force limiting device is arranged longitudinally axially sequentially with the second force limiting device (K2), or conversely, wherein the first force limiting device (K1) is arranged longitudinally axially sequentially with the third force limiting device and the third force limiting device is cascaded with the second force limiting device (K2). Modular surgical instrument system (100) comprising different handles (101, 10T, 101"), different shafts (102, 102', 102") with different proximal end pieces (20, 20', 20") and different tool tips (103, 103', 103"), wherein the different handles (101, 10T, 101"), the different shafts (102, 102', 102") and the different tool tips (103, 103', 103") can be combined to form a modular surgical instrument (10), in which the tool tip (103, 103', 103") is arranged at a distal end of the shaft (102, 102', 102") and has a longitudinally axially disposed in the shaft (102, 102', 102") movable actuating element (21) is operable, which is in operative connection with the handle (101, 101', 101"), which is arranged at a proximal end of the shaft (102, 102', 102"), characterized in thatthat the modular surgical instrument system comprises an overload protection device (1) according to at least one of claims 1 to 10. Modular surgical instrument system (100) according to claim 11, characterized in that each proximal end piece (20, 20', 20") is assigned to one of the tool tips (103, 103', 103"), which differ with respect to the predetermined limit force. Modular surgical instrument system (100) according to claim 11 or 12, characterized in that the overload protection device (1) is arranged in the handles (101, 101', 101"). Modular surgical instrument (10) comprising a handle (101, 101', 101"), a shaft (102, 102', 102") and a tool tip (103, 103', 103"), which are selected from a modular surgical instrument system (100) comprising different handles (101, 101', 101"), different shafts (102, 102', 102") with different proximal end pieces (20, 20', 20") and different tool tips (103, 103', 103"), wherein the tool tip (103, 103', 103") is arranged at a distal end of the shaft (102, 102', 102") and has a longitudinally axially arranged in the shaft (102, 102', 102") movable actuating element (21) is operable, which is operatively connected to the handle (101, 101', 101"), which is arranged at a proximal end (20, 20', 20") of the shaft (102, 102', 102"), characterized in thatthat the modular surgical instrument system (100) is a modular surgical instrument system (100) according to at least one of claims 11 to 13, which has an overload protection device (1) according to at least one of claims 1 to 10, wherein the proximal end piece (20, 20', 20") of the selected shaft (102, 102', 102") is associated with the selected tool tip (103, 103', 103") and provides an operative connection with the overload protection device (1) adapted to its predetermined limit force.

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