MEDICAL INSTRUMENT WITH CLEANING-OPTIMIZED SPRING UNIT

Description

Technical area

[0001] The present disclosure relates to a medical, in particular surgical, instrument, preferably a manually operable handheld instrument, having at least two (a first and a second) handle elements, wherein the handle elements in particular comprise metal as their material, particularly preferably are made entirely of metal as their material (for example, stainless steel as the material), and the handle elements are pivotally mounted relative to one another via a bearing, in particular via a joint, and a spring unit / spring-elastic assembly having two spring ends, each connected to one of the two handle elements, so that upon pivoting at least one of the two handle elements from a basic position (against an elastic force of the spring unit), a pivoting back into the basic position can be carried out / realized / achieved by means of the spring unit. In addition, the disclosure relates to a method for producing a medical instrument. State of the art

[0002] Medical and surgical (hand) instruments currently utilize return springs designed as leaf springs that make extensive contact with a branch or handle element over a large area. Both the leaf spring and the handle element have large, continuous surfaces facing each other that, starting from the common contact surface, continuously move away from each other. One could also say that the leaf spring and handle element have a partially circular / arc-shaped contour with different radii in the attachment section and, as a result, the distance between them gradually increases (starting from zero). While one surface of the leaf spring is in direct, extensive contact with another surface of the handle element, the two surfaces move away from each other outside the attachment section, forming a very small gap that gradually increases.As a result, the contact surface of medical instruments is very difficult to clean and sterilize. Furthermore, the contact area of the return spring and handle element is subject to contact corrosion or bimetallic corrosion.

[0003] DE 10 2017 114 260 A1, for example, discloses a medical hand instrument in which a one-piece return spring is connected to a handle element by means of a positive fit. A disadvantage of this instrument, however, is that complex milled receptacles must be provided on the branch or handle element. Furthermore, a one-piece return spring is provided, so that a linearly increasing, high spring force is created when the hand instrument is closed. This spring force counteracts the force applied by a user, such as a surgeon, particularly in a closed position, and thus reduces the maximum manually applicable force. Furthermore, the spring exhibits a high degree of deformation, resulting in an increased risk of the return spring breaking during continuous use. Documents JPH0531772U, US3921478A, CN110785139A, DE10137915A1, and EP2787903 disclose prior art devices. Summary

[0004] The problem underlying the subject matter of the application is solved by an instrument according to the invention having the features specified in claim 1, and by a method according to the invention having the features specified in claim 9. Further embodiments are specified in the subclaims. The objects and aims of the present disclosure are to avoid or at least mitigate the disadvantages of the prior art and, in particular, to provide a medical, in particular surgical, instrument and a method for producing a medical instrument that offers good cleanability, is simple and cost-effective to manufacture, and at the same time keeps a force for pivoting the handle elements constant over a large, in particular entire, travel range of the instrument. Furthermore, the instrument should, in particular, be small in size, have a simple design, be easy to handle, and simplify maintenance.

[0005] The objects and aims with regard to a medical instrument are achieved by the features of claim 1 and with regard to a method for producing a medical instrument by the features of claim 9.

[0006] The present disclosure therefore relates to a medical instrument with two handle elements (handles, handle levers, lever arms) that can be pivoted relative to one another and a spring unit arranged between the handle elements. The preferably U- or V-shaped spring unit has two (spring) ends. Each of the two spring ends is fastened to a corresponding / associated one of the two handle elements, so that when at least one of the two handle elements is pivoted from a basic position, it pivots back to this basic position. This means that if one of the two handle elements is manually pivoted by a user of the instrument, the spring unit can pivot the pivoted handle element back to its basic position as soon as the user releases the pivoted handle part. The instrument preferably has load arms opposite a hinge that pivotally connects the handle elements.The medical instrument can also be designed so that both handle elements pivot during use. If only one handle element is designed to pivot, the other handle element serves only as a counter-bearing for the user's hand during pivoting. In particular, the medical instrument has a distal active section, such as a clamping section (clamping / grasping jaws) or cutting section (cutting blades), etc., that can be actuated via the proximal handle section.

[0007] According to the present disclosure, the instrument is provided with such a spring unit, which extends in particular from at least one of the two spring ends, particularly preferably from both spring ends, to a bearing of the handle elements, in particular a joint, particularly preferably a hinge, or a pivot axis, and is adapted to provide a constant / consistent force / spring force / restoring force when pivoting the handle elements, in particular over the entire closing path of the instrument (entire possible pivoting movement). To realize the constant spring force, the instrument is preferably provided with an at least two-part spring unit, which has at least a first spring section, in particular a first spring leg, and a (separate) second spring section, in particular a second spring leg, which are connected to one another, in particular coupled to one another in an at least partially movable manner.When the two arms or handle elements are pressed together from their home position, the spring force of the spring unit (when pivoting into a closed position) can be maintained evenly and homogeneously, particularly across the entire closing travel range. A linear increase in spring force is avoided. This special design supports the user of the instrument and ultimately increases the potentially maximum closing force that can be applied, counteracting user fatigue.

[0008] In addition, the spring unit or the spring ends are connected to the handle elements in a specially adapted manner. Specifically, at least one spring end is positively inserted into a corresponding geometric receptacle / recess formed on the handle element and is firmly bonded to the corresponding handle element. Inserting the spring end into the recess causes the spring end to be geometrically fixed relative to the handle element in at least one direction (and in particular in the opposite direction) by the positive fit or undercut (and furthermore, in particular, rotation).This blocks at least one, in particular at least two possible degrees of freedom of movement (out of a total of six degrees of freedom: three translational and three rotational) of the spring end relative to the associated handle element, in particular in a direction of the handle element longitudinal axis and in particular a rotation about a rotation axis perpendicular to the handle longitudinal axis and perpendicular to the spring end longitudinal axis.

[0009] This design enables a simple and cost-effective construction of the medical instrument, which is easy to clean and stretch, and meets the high requirements of a medical technology product. In particular, the spring unit is connected to the handle elements in a non-losable / loss-proof manner. Since the spring unit in particular only comes into contact with the associated handle element at at least one spring end in all pivoting positions, especially in the basic position, a custom-adapted geometric design is possible thanks to the defined connection point between the spring end and the handle element, in particular the receptacle / recess. If, in addition, the spring end and the handle element are materially bonded to one another in such a way that a closed surface is formed in the connection area, good cleaning is ensured.In the case of a recess, at least one of the two spring ends must protrude into a recess and be materially connected to the handle element so that a gap that forms between the recess and the spring end is hermetically sealed towards an instrument environment in order to prevent the formation of germs.

[0010] In other words, the spring unit, in particular a spring leg, and at least one grip element are adapted such that a spring end can be inserted into the grip element or branch and is integrally connected to it, in particular in such a way that no dirt can penetrate or become trapped in the interface, for example in a gap. In particular, at least one of the two spring legs is inserted into the branch and further integrally connected in such a way that a hermetically sealed surface without undercuts is present at the connection point. Inserting the spring end into a corresponding recess also prevents buckling.

[0011] The spring unit and the handle elements can be designed separately and manufactured cost-effectively and are securely connected to each other during assembly.

[0012] In particular, a contact point / connection point of the two spring ends can also be designed to be separable without tools in order to ensure easy and effective cleaning or replacement of the spring unit.

[0013] In other words, at least one of the two spring ends projects (positively) into a corresponding, in particular complementary, recess (as a receptacle) formed in the associated handle element, which recess forms in particular at least one undercut in the distal direction along a handle longitudinal axis and is materially connected to the associated handle element, in particular in such a way that a gap between the recess and the spring end is hermetically sealed towards an instrument environment.

[0014] The term "basic position" defines the position of the pivoting handle elements relative to each other, into which they move without external (manual) force, only limited by the spring unit. This basic position can, in particular, be a (geometrically determined) maximum opening position of the instrument.

[0015] The spring unit therefore preferably extends from at least one spring end towards a pivot axis or a bearing of the medical instrument, in particular distally. In particular, at least one spring extends from its spring end towards the pivot axis or the bearing, preferably distally. In other words, the spring unit, in particular the at least two springs, can run between the two pivotable handle elements along these handle elements towards a pivot axis or to a bearing, in particular a hinge. The spring unit or the springs therefore do not protrude proximally or away from the bearing. This allows even better use of installation space and further improves ergonomics. The surgeon does not have to be careful not to accidentally catch the spring unit on external objects such as a surgical drape or to inadvertently damage external objects, for example tissue.The spring unit is located, so to speak, in particular between the handle elements or is arranged between the handle elements (at a similar height to a longitudinal axis of the instrument) and is, to a certain extent, enclosed by the handle elements and protects the spring unit (laterally) outwards by the handle elements.

[0016] In particular, the recess can be provided on the inside of the associated handle element (i.e., opposite the other handle element) and / or a longitudinal axis of the recess can point towards the opposite handle element. Because the recess is open laterally inward and the spring end is inserted into it, the spring unit is held captively on the one hand, and on the other hand, the spring force can be transferred particularly well to the handle element. The recess is therefore not formed at the proximal end of the handle element, but on the inside of the handle element. In conjunction with the spring unit, this optimizes the installation space and arrangement of the spring unit.

[0017] Advantageous embodiments are claimed in the subclaims and are explained in particular below.

[0018] According to one aspect of the present disclosure, the at least one spring end and the associated grip element can be welded and / or soldered, in particular with an additional brazed solder, and / or adhesively bonded, in particular at a contact region / contact boundary between an outer surface of the spring end and an inner surface of the associated grip element, which is opposite the other grip element. These integral connections are durable, easy to create, and, particularly in the case of a circumferential weld or solder seam, represent a particularly hermetic boundary with respect to the environment, into which no germs can penetrate and, moreover, are sterilizable even at high temperatures.

[0019] According to a further aspect of the present disclosure, at least one of the two spring legs can have a projection angle between the, in particular, protruding, spring end and the associated grip element (as seen distal to the spring end in the longitudinal axis of the branch) of at least 30°, preferably of at least 45°, very preferably of at least 70°, and in particular of exactly 90°. The projection angle can also be said to define an angle between a grip element longitudinal axis and a spring end longitudinal axis. This minimum projection angle ensures that a gap with a sufficiently obtuse angle is formed, which can be easily cleaned.

[0020] In particular, a dimension from an end face of the spring end along a straight section of the spring end is at least 2 mm, preferably at least 5 mm, particularly preferably at least 10 mm, in order to realize a minimum gap height. In particular, a gap that forms between a spring leg and the associated handle element has a minimum height of 1 mm, preferably 3 mm, particularly preferably 5 mm. Preferably, a distance in the direction perpendicular to the handle element longitudinal axis between an inner surface of the handle at the spring end and a facing surface of the spring unit after a proximal bend and / or at a point at a length of the spring leg of 15% of the total length (measured from the spring end), in at least the basic position, is at least 1 mm, preferably 3 mm, and particularly preferably 5 mm. This allows the instrument to be easily cleaned.

[0021] Preferably, at least one spring leg can be designed as a leaf spring or as a spring steel wire, and in particular, can be made of the material X20CR13 or, according to DIN EN 10088, the material 1.4021, or can be made entirely of this material. If the spring leg or the entire spring unit is made of this material, it provides very good mechanical properties, very good polishability, good forgeability, coupled with good chemical resistance, and satisfactory weldability.

[0022] According to one embodiment, the spring unit can be designed in two parts in the form of two leaf springs or two spring steel wires, which are connected / coupled to one another via a distal spring coupling, in particular via a distal fork-nose connection or a distal ball-socket connection or a distal Yt connection. Leaf springs are simple and cost-effective to manufacture, in particular can be easily and irreversibly bent into the desired shape, and offer reliable spring forces. Spring steel wires, on the other hand, are also cost-effective and meet the mechanical property requirements for corresponding forming. In particular, with their circular cross-section, they have no edges, so they are particularly easy to clean. In the two-part form with the distal spring coupling, the spring forces remain constant over the entire closing travel of the instrument orWhen the handle elements are pivoted against each other, the spring force remains constant in every pivoting position. A linear increase in spring force, as with a one-piece spring element, is avoided.

[0023] According to a further embodiment, in the case of an at least two-part spring unit, at least one of the two spring legs, in particular both spring legs, can be S-shaped, in particular with a first proximal bending radius and / or a second opposing distal bending radius, wherein a curve angle / bending angle between the tangential sections of the proximal bending radius (or the partial circle segment) is preferably 90° and / or 45° between the distal bending radius. The S-shaped design supports a spring-elastic force and geometric change or approximation of the spring leg relative to the handle element, in particular such that it does not come into contact or abutment with the handle element in any pivoting position, but at least not in the basic position of the handle elements relative to one another.

[0024] In particular, the recess can be a blind hole, a groove, or a slot, particularly a through slot. A spring steel wire with (approximately) the same diameter (press fit or clearance fit; similar to a pin in a bore) can be inserted into a blind hole with a defined diameter. If a leaf spring is used as the spring leg, the leaf-shaped / plate-shaped spring end (with a relatively small height compared to width) can be inserted into an elongated groove. If the groove is continuous, the leaf spring can also be inserted laterally into the groove instead of being inserted along its longitudinal axis. The groove can also have an undercut in the insertion direction, and the spring end can have a corresponding projection, so that when inserted laterally, a positive connection is formed in the direction of the spring end's longitudinal axis.In addition, the recess can have a depth (in the direction of the longitudinal axis of the spring ends) of at least 2 mm and / or a maximum of 6 mm. The minimum depth ensures sufficient mechanical load-bearing capacity of the spring leg or spring unit.

[0025] According to a further aspect, the spring unit can be adapted relative to the gripping elements such that the first and / or second spring leg, at least in the basic position, and in particular in all positions where the gripping elements are pivoted relative to one another, only comes into contact with the associated gripping elements at the spring end as the connection point. This prevents abrasion and improves the durability of both the spring unit and the gripping elements.

[0026] Preferably, the spring unit may have a distal spring coupling which is mounted in a releasably displaceable and / or pivotable manner relative to one another.

[0027] Preferably, the recess and / or the spring end are square or oval (and not circular) in shape, so that even one degree of rotation about the spring end's longitudinal axis is blocked. In particular, the spring end and recess are shaped such that only a single geometric degree of freedom remains in one direction, which is further preferably subjected to a preload force, for example, caused by the spring unit, in order to securely hold the spring unit. Alternatively or additionally, the spring end can also be integrally connected to the handle element.

[0028] Preferably, the medical instrument can be designed as a multi-jointed branch forceps. In particular, the medical instrument can be designed as a multi-ratio, in particular a double-ratio, forceps, particularly preferably as a double-ratio rongeur. The spring structure disclosed here is particularly suitable for this type of instrument. Such an instrument type of a multi- or double-ratio forceps, in particular a rongeur, has several joints that are designed to be particularly stable. As a result, however, the joints also have a higher overall internal friction (multiple joints result in a larger friction surface), which requires a higher restoring force of the spring (unit). This represents a difference from the requirements for a restoring spring of neurological scissors or forceps.With double-action rongeurs, it is particularly disadvantageous if the spring force increases during the closing process, as the spring force is already very high at the beginning of the closing process. This makes the manual force required by the user when closing the double-action rongeurs particularly challenging, particularly since the double-action rongeurs are intended to separate pieces of bone, a task that in itself requires considerable strength. In particular, it is advantageous for these double-action rongeurs if the recess(es) or receptacle(s) in the handle element(s) run at an angle to a bearing, in particular a joint, or a pivot axis, as this configuration reliably prevents the spring ends from slipping out under high spring force.In contrast, vertical receptacles or recesses, i.e. receptacles that extend perpendicular to a longitudinal axis of the associated handle element, or even those that extend towards a user, are particularly susceptible to being pushed out of the recess or receptacle when high force is applied, rendering the instrument unusable and also endangering the safety of a patient.

[0029] The objects and aims of the disclosure are achieved with regard to a method for producing a medical instrument with a spring unit, in particular an instrument of the present disclosure, by the steps, in particular in this order: bending at least one spring leg, in particular a leaf spring or a spring steel wire; shaping, in particular embossing and / or grinding, a distal section of the spring leg, preferably a distal grinding of a curve; inserting the at least one spring leg into a recess formed in a handle element, in particular in the form of a blind hole or a groove; preferably aligning the spring leg with respect to the associated handle element; materially connecting, in particular welding and / or soldering, the spring leg to the associated handle element.Through these steps of the method, a medical instrument assembly with at least one handle element and a spring leg is provided that is simple and cost-effective to manufacture and easy to clean. Manufacturing, including simple assembly, is easy to implement and also cost-effective.

[0030] Preferably, after the step of materially bonding, the method may comprise the step of hardening the spring leg with the associated handle element and / or the step of brushing and / or blasting the spring leg with the associated handle element.

[0031] Furthermore, the method may comprise a step of overall assembly of the instrument.

[0032] In other words, a medical instrument can be provided in which preferably two leaf springs or two spring wires / spring steel wires, one per branch (handle element), are inserted and / or welded and / or soldered and / or glued into blind holes or grooves in the branches. Since the springs do not touch the branches anywhere except at their connecting parts (at least in the basic position), good cleaning and cleanability are guaranteed. The two-part spring, which in spring concepts are in contact distally via spring force, through a fork-nose connection or a ball-socket connection, has the advantage that when the medical instrument, particularly in the form of pliers, is closed, the spring force does not increase linearly. The closing forces therefore remain almost constant. Short description of the characters

[0033] The present disclosure will be explained in more detail below using preferred embodiments with reference to the accompanying figures. They show: Fig. 1 is a plan view of a medical instrument of a first preferred embodiment, in which the spring unit is connected to the handles in a form-fitting and material-locking manner; Fig. 2 is a detailed view of a distal spring coupling of the two leaf springs of the spring unit of the medical instrument of Fig. 1; Fig. 3 is a plan view of a medical instrument of a further, second preferred embodiment, in which the spring unit has a distal Yt connection; Fig. 4 is a detailed view of a distal connection of the spring unit of a further preferred embodiment of an instrument in the form of a ball-socket connection; Fig. 5 is a plan view of a spring unit of a further preferred embodiment of a medical instrument; Fig. 6 is a plan view of a medical instrument of a preferred embodiment, in which the spring unit of Fig. 5 is inserted; Fig. 7 a detailed view of the distal spring coupling of the spring unit from Fig. 6 ; and Fig. 8 is a flowchart of a method for manufacturing a medical instrument according to a preferred embodiment.

[0034] The figures are schematic in nature and are intended solely to assist in understanding the present disclosure. Like elements are provided with the same reference numerals. The features of the various embodiments may be interchanged. Any disclosure related to the method according to the present disclosure also applies to the medical instrument of the present disclosure, just as any disclosure related to the medical instrument also applies to the method according to the present disclosure. Detailed description of preferred embodiments

[0035] Fig. 1shows a partial view of a medical instrument 1 of a first preferred embodiment in a basic position. The instrument 1, in the form of a hand instrument, is designed as a pincer-type forceps. The instrument 1 has two levers 2, 4, which are pivotally connected to one another via a hinge 6. The two levers 2, 4 can thus be pivoted relative to one another in a pivot plane S, similar to scissors or grasping forceps. The proximal sections of the levers 2, 4 (proximal to the hinge 6 and facing the user) form a handle section 8 with corresponding handle elements or handles 10, 12, which are designed essentially symmetrically to one another with respect to a longitudinal axis of the instrument. The handle section 8 is also designed symmetrically to the pivot plane S.

[0036] Between the first handle 10 and the second handle 12, a two-part spring unit 14 in the form of a two-part leaf spring is provided, which forms a first spring leg 16 and a second spring leg 18 of the spring unit 14 and which are detachably and displaceably and pivotably coupled to one another at their respective distal ends.

[0037] The respective free spring ends 20, 22 of the spring legs 16, 18 protrude into a recess in the form of a groove formed in the respective handles 10, 12, which is formed on the inside of the handles 10, 12 on opposite inner surfaces 26, 28. The recesses 24 are linear and symmetrical to one another with respect to a longitudinal axis of the instrument and point (seen in plan view) slightly obliquely forward in the distal direction. The spring ends 20, 22 protrude into the recesses 24 and thus form a cantilever angle α between the distally located outer side of the leaf spring (spring end section), i.e. the surface facing distally, and the inner surface 26 or 28. This also essentially corresponds to an angle between a branch longitudinal axis or handle longitudinal axis along the handle 10, 12 and the spring end 20, 22 or.a spring end section adjoining the spring end 20, 22 or a spring end longitudinal axis.

[0038] The spring ends 20, 22 are also integrally connected, namely welded, to the inner surfaces 26, 28, so that a gap between the recesses 24 and the respective spring ends is hermetically sealed from the instrument's surroundings. This ensures, on the one hand, that the spring unit 14 is securely attached to the instrument 1 or connected thereto, and, on the other hand, that gaps and other hard-to-reach spaces in which germs could settle are prevented.

[0039] This special design of the instrument 1, with both a positive and material connection between the spring unit 14 and the handles 10, 12, and the special projection of the spring ends 20, 22 from the handles 10, 12, enables cost-effective production of the instrument 1, high mechanical strength, a long service life, and exceptionally good cleanability, particularly sterilizability, since a sufficiently large distance between the spring legs 16, 18 and the handles is ensured. Since a projection angle α of at least approximately 45° is selected, a sufficiently obtuse angle is formed between the spring ends 20, 22 and the handles 10, 12, which also promotes effective cleaning.In particular, the positive fit with the recess 24 and the associated spring end 10, 12 ensures sufficient mechanical strength of the spring unit 14, so that the instrument 1 is durable and its function is guaranteed even after a very high number of pivoting movements. Tearing is prevented. The weld seam, in particular, ensures sealing against the environment and additionally increases the mechanical strength of the connection.

[0040] The two leaf springs are made of material 1.4021 according to DIN EN 10088, which provides very good mechanical properties, good polishability coupled with good chemical resistance and weldability.

[0041] In Fig. 2 is a detailed distal spring coupling 30 of the instrument 1 on Fig. 1shown in the form of a distal fork-nose connection, viewed from distal to proximal. The free distal end of the first spring leg 16 has a nose 32, which is enclosed between a fork 34 with two prongs or arms 36 or side walls, which is longitudinally displaceable and pivotable in the instrument's longitudinal axis. In this way, during a pivoting movement of the instrument 1, the distal spring coupling 30 can follow a movement and the spring force remains constant over the entire pivoting path. In addition, assembly is simplified. The two distal ends are detachably coupled to one another in that, due to their preload force, the nose 32 and fork 34 engage and are elastically pressed against one another. In a sense, a spring-loaded hinge is created at the distal end as the spring coupling 30.

[0042] Fig. 3shows a medical instrument 1 of a further, second preferred embodiment. In contrast to the first embodiment, the spring unit 14 and the associated recesses 24 are designed differently. Specifically, the two spring legs 16, 18 are not designed as leaf springs but as S-shaped spring steel wire that projects into a recess 24 designed as a blind hole. In addition, the distal coupling 30 is designed as a Yt-connection with a Y-shaped distal end section / Y-section 38, which is interlaced and detachably connected to a T-shaped distal end section / T-section 40. The Y-section 38, like the entire second spring leg 18, has a circular cross-section in its two parallel Y-arms 42. The Y-arms 42 converge in a curved manner at a fork 44.The T-section 40 has a strut 46 with a circular cross-section that is perpendicular to a longitudinal axis of the first spring leg 16, forming a T-shaped or X-shaped section that is in contact with the Y-section in an interlaced manner. Both spring legs 16, 18 are prestressed against each other. In particular, in this embodiment, the... Fig. 3The struts 46 are arranged distally opposite the two Y-arms 42, so that the struts 46 form a type of stop for the Y-section 38 in the distal direction. In other words, the spring leg 16 is guided proximal to the two struts 46 between the two Y-arms 42. Due to the preload force, particularly when the two handles 10, 12 are pressed together, the Y-section 38 is pushed distally, but blocked by the two struts 46 running transversely to the spring leg 16. On the other hand, the T-section 40 is held in the fork of the Y-section 38, so that the two spring legs 16, 18 are detachably coupled to one another and provide a constant spring force over the entire pivoting movement path.

[0043] This embodiment with a Yt connection enables good elastic bending of the two spring legs 16, 18, which are made of spring steel wire and are bent in an S-shape (irreversibly) or have such a course along their spring leg longitudinal axis, with simultaneous secure (detachable) connection at the distal spring coupling 30. This design is particularly cost-effective in production.

[0044] Fig. 4 shows a detailed view of a distal portion of the spring unit 14, here the spring coupling 30 of another preferred embodiment. The distal spring coupling 30 of Fig. 4 can be used in instrument 1 instead of the Yt connection in Fig. 3 In contrast to the spring coupling 30 of the second embodiment of Fig. 3 The spring coupling of the Fig. 4Instead of a Yt connection, a ball-socket connection is used with a distal ball 48 formed on the first spring leg 16 and a socket 50 formed on the second spring leg 18. Specifically, the ball 48 rests in a bowl-shaped receptacle of the socket 50 under spring preload, and a detachable connection or coupling is created between the distal ends (countering the preload of the spring unit 14). This special coupling has the effect that when the handles 10, 12 are pivoted from a basic position, the two spring legs 16, 18 are initially pushed distally due to their freedom of movement and deform elastically. However, since a (ball) joint has been created by the ball 48 and the socket 50, the distal ends can shift and pivot against each other, so that a spring force remains uniform or even constant during a pivoting movement, such as a closing movement in a closing direction.an almost constant spring force is achieved.

[0045] Fig. 5 shows a spring unit 14 according to a further preferred embodiment, which is not yet connected to the handles (and is not yet pre-tensioned). The spring legs 16, 18 are formed symmetrically to each other except for the distal end. The proximal spring ends 20, 22 have a bend with a first proximal bending radius 60 (in particular a radius R6) which is bent by 90° in a (in Fig. 5 seen on the second spring leg 18) curves to the right. After a short straight section (especially over a length of 9mm) there is a (in Fig. 5seen; second spring leg 18) curves to the left by a bending angle / curve angle β of 45° with a larger distal bending radius 62 (approximately or exactly three times the bending radius, in particular R17). This is followed by a straight section, the distal end of which curves slightly to the left (in particular by approximately 5°) and has a spherical curve at the end.

[0046] The first spring leg 16 is S-shaped, symmetrical to the second spring leg 18, but has a cup-shaped recess 52 at its distal end, the cup-shaped / shell-shaped receptacle of which is open towards the second spring leg 18 or the distal spherical curve. The spherical distal end of the second spring leg 18 is inserted or fitted into this receptacle. A maximum dimension 56 in the pivot plane S in the direction perpendicular to the instrument's longitudinal axis, in the non-preloaded state, is in particular approximately 1.3 times a maximum dimension in the pivot plane S in the direction of the instrument's longitudinal axis. A dimension 58 of a projection of the spring end 20 in the pivot plane S in the direction perpendicular to an instrument's longitudinal axis is approximately 20% of the maximum dimension 56. In particular, a dimension 58 of the projection is 11 mm.In particular, the spring end 20, 22 has a straight section which extends approximately over one third or half of the dimension 58 of the projection, in particular over 5 mm.

[0047] Fig. 6 and Fig. 7 show a medical instrument 1 according to another preferred embodiment in a top view and a detailed top view in the area of the distal spring coupling 30. The medical instrument 1 is designed as a multi-jointed forceps and has a distal active section 64 in the form of a forceps. The spring unit 14 of Fig. 5 is used in this instrument. Specifically, the two spring ends 20, 22 on the inner surfaces 26, 28 extend into recesses (not shown) of the handles 10, 12.

[0048] The overhang angle α is larger than in the first embodiment and amounts to approximately 80°. The proximal bending radius 60 adjoins the spring end 20, 22. Consequently, a defined gap is provided on the inside of the handles 10, 12. This gap has a large minimum size and ensures good cleanability due to the rounded edges, both due to the circular cross-section of the S-shaped spring steel wire and the bending radius 60. Furthermore, the instrument 1 can be manufactured easily and cost-effectively.

[0049] Fig. 8 shows a flowchart of a method for manufacturing an instrument 1 according to a preferred embodiment. In this embodiment, the method produces an instrument 1 according to the present disclosure.

[0050] In a first step S1, both a first and a second spring leg 16, 18 are bent into the correct shape. Specifically, the spring leg 16, 18 is formed from a spring steel wire or a leaf spring and is bent into an S-shape (according to a sketch).

[0051] In a step S2, the distal sections of the two spring legs 16, 18 are formed, which will later be distally coupled to each other. Specifically, the free end of the first spring leg 16 is stamped to form a flat, spoon-shaped or cup-shaped structure / cup 52 that forms a bowl-shaped receptacle. The other distal end of the second spring leg 18 is ground distally to obtain a spherical rounding 54.

[0052] The order of steps S1 and S2 is not important, so these two steps can also be performed in reverse order.

[0053] This is followed by step S3 of inserting the two spring legs 16, 18 into a respective recess 24 formed in the handles 10, 12 in the form of a blind hole, so that a positive connection is created between the spring legs 16, 18 and the associated handles 10, 12.

[0054] Subsequently, in a step S4, the two spring legs 16, 18 are aligned relative to the corresponding handles 10, 12. In particular, at this point, the distal spherical curve can be loosely inserted into the complementary socket 52 and the two spring legs 16, 18 can be preloaded against each other to verify correct alignment.

[0055] In this aligned position, the spring legs are then joined together in step S5. In this case, the spring legs are welded to the associated handle element, in particular with an additive. Specifically, a weld seam is formed on the handles 10, 12 around the spring ends 20, 22 or at the end sections, so that a gap that forms between the spring ends 20, 22 and the recess 24 is hermetically sealed.

[0056] After step S5 of the material-locking connection, step S6 of hardening the spring legs 16, 18 with the associated handle element 10, 12 takes place. In the present case, in particular, the entire instrument 1 or all components are hardened.

[0057] In step S7, the handles 10, 12 and the spring unit 14 are brushed and sandblasted to create a smooth surface, particularly at the connection point between the handle 10, 12 and the spring legs 16, 18.

[0058] Finally, in step S8, the complete assembly of instrument 1 follows. List of reference symbols

[0059] 1Medical instrument 2First lever 4Second lever 6Hinge 8Handle section 10First handle element 12Second handle element 14Spring unit 16First spring leg 18Second spring leg 20First spring end 22Second spring end 24Recess 26First inside surface 28Second inside surface 30Distal spring coupling 32Nose 34Fork 36Fork arm 38Y-section 40T-section 42Y-arm 44Y-fork 46Strut 48Ball 50Socket 52Embossed 54Curved end 56Dimension 58Protrusion dimension 60(First) proximal bend radius 62(Second) distal bend radius S Swivel plane α Cantilever angle β Curve angle S1Step Bending spring leg S2Step Shaping distal end S3Step Inserting spring leg S4Step Aligning spring leg with respect to handle S5Step Bonding S6Step Hardening S7Step Brushing S8Step Assembly

Claims

1. A medical, in particular surgical, instrument (1), having two gripping elements (10, 12) which have metal as material, are particularly entirely made from metal as material, and which are pivotably mounted relative to each other via a bearing, in particular via a joint, and a spring unit (14), which has two spring ends (20, 22) which are each connected to one of the two gripping elements (10, 12), so that when at least one of the two gripping elements (10, 12) pivots out of a base position, pivoting back into the base position can be carried out via the spring unit (14), characterized in that the spring unit (14) extends from at least one of the two spring ends (20, 22), preferably from both spring ends (20, 22), toward the bearing, in particular joint and is adapted to provide a substantially constant spring force when the gripping elements (10, 12) pivot, is in particular formed of at least two parts and has a first spring leg (16) and a second spring leg (18), and at least one of the two spring ends (20, 22) protrudes into an indentation (24) formed in the associated gripping element (10, 12) and / or is firmly bonded to the associated gripping element (10, 12), in particular so that a gap between indentation (24) and spring end (20, 22) is hermetically sealed toward an instrument environment.

2. The medical instrument (1) according to claim 1, characterized in that the at least one spring end (20, 22) and the associated gripping element (10, 12) are welded and / or soldered together, in particular brazed with an additive, and / or glued, in particular at a contact region between an outer surface of the spring end (20, 22) and an internal surface (26, 28) of the associated gripping element (10, 12), which is opposite the other gripping element (10, 12).

3. The medical instrument (1) according to claim 1 or 2, characterized in that at least one spring end (20, 22), in particular at least one of the two spring legs (16, 18), has a cantilever angle (α) between the in particular protruding spring end (20, 22) and the associated gripping element (10, 12) of at least 30°, preferably of at least 45°, most preferably of at least 70°, and in particular of exactly 90°.

4. The medical instrument (1) according to any of the preceding claims, characterized in that at least one spring leg (16, 18) is configured as a leaf spring or spring steel wire and, in particular, has the material X20CR13 or, according to DIN EN 10088, the material 1.4021 as the material, in particular is made entirely of this material.

5. The medical instrument (1) according to claim 4, characterized in that the spring unit (14) is configured in two parts in the form of two leaf springs or two spring steel wires, which are detachably coupled to each other via a distal spring coupling (30), in particular via a distal fork-nose connection (32, 34) or a distal ball pan connection (48, 50) or a distal Y-t connection (38, 40).

6. The medical instrument (1) according to any of the preceding claims, characterized in that at least one of the two spring legs (16, 18), in particular both, is S-shaped with in particular a first proximal bending radius (60) and / or an opposing, in particular larger, distal bending radius (62), a bending angle between the tangential portions of the proximal bending radius preferably being 90° and / or of the distal bending radius being 45°.

7. The medical instrument (1) according to any of the preceding claims, characterized in that the indentation (24) is a blind hole or a groove or a slit, in particular a passage slit, and in particular has a depth of at least 2 mm and / or a maximum of 6 mm.

8. The medical instrument (1) according to any of the preceding claims, characterized in that the spring unit (14) is adapted with respect to the gripping elements (10, 12) in such a way that the spring unit (14), in particular the first spring leg (16) and / or the second spring leg (18), in at least the base position, in particular in all positions in which gripping elements (10, 12) are pivoted to each other, only comes into contact with the associated gripping elements (10, 12) at the spring end (20, 22) as the connection point.

9. A method for manufacturing a medical instrument with a spring unit, in particular an instrument (1) according to any of claims 1 to 8, characterized by the steps, in particular in this order: - bending (S1) at least one spring leg (16, 18), in particular of a leaf spring or a spring steel wire; - forming (S2), in particular imprinting and / or grinding, a distal portion or end of the spring leg (16, 18), preferably grinding a distal rounding; - inserting (S3) the at least one spring leg (16, 18) into an indentation (24) formed in a gripping element (10, 12), in particular in the form of a blind hole or a groove; - preferably orienting (S4) the spring leg (16, 18) relative to the associated gripping element (10, 12), in particular with an extension of the inserted end of the spring leg (16, 18) toward a bearing, preferably joint, of the medical instrument, via which the gripping elements are pivotably mounted relative to each other; - firmly bonded connecting (S5), in particular welding and / or soldering, the spring leg (16, 18) to the associated gripping element (10, 12).

10. The method according to claim 9, characterized in that, after the step of firmly bonded connecting (S5), the method comprises the step of tempering (S6) the spring leg with the associated gripping element and / or comprises the step of brushing (S7) and / or sandblasting the spring leg (16, 18) with the associated gripping element (10, 12).