Medical device having a spring unit optimized for cleaning - Patents.com

Abstract

The present invention relates to a medical, in particular surgical, instrument (1), comprising two handle elements (10, 12) pivotally mounted relative to one another, and a spring unit (14) having two spring ends (20, 22), each spring end being connected to one of the two handle elements (10, 12) in such a way that, when at least one of the two handle elements (10, 12) is pivoted from a starting position, the spring unit (14) is capable of pivoting said handle element back to its starting position. and the spring unit (14) is configured to provide a substantially constant spring force when the handle elements (10, 12) are rotated, in particular it is formed in at least two parts, with a first spring leg (16) and a second spring leg (18), at least one of the two spring ends (20, 22) protruding into a recess formed in the associated handle element (10, 12), in particular it is materially bonded to the associated handle element (10, 12) such that a gap between the recess and the spring end (20, 22) is hermetically sealed against the instrument environment. The invention also relates to a method for manufacturing a medical instrument according to an additional independent claim.

Description

[Technical field]

[0001] The present disclosure relates to a medical, in particular a surgical instrument, preferably a manually operable hand instrument, comprising at least two (first and second) gripping elements, in particular having a metal as a material, particularly preferably made entirely from a metal as a material (e.g. stainless steel as a base material), which 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 gripping elements, such that when at least one of the two gripping elements pivots from a base state (against the elastic force of the spring unit), a pivoting back to the base state via the spring unit is possible / achievable / achievable. The present disclosure also relates to a method for manufacturing the medical instrument. [Background technology]

[0002] Currently, in medical or surgical (hand) instruments, return springs are used that are configured as leaf springs and are in contact with the branch or gripping element over a large area. Both the leaf spring and the gripping element have large continuous surfaces facing each other, which start from a common contact bearing surface and move away from each other continuously. It can also be said that the leaf spring and the gripping element have semicircular / arc-shaped contours with different radii at the fastening part, which continuously increase the distance between them (from zero). Some surfaces of the leaf spring are in direct contact with some surfaces of the gripping element, while the two surfaces move away from each other on the outside, forming a very small gap between them, which gradually increases. As a result, cleaning and sterilization of the medical instrument is very difficult in the area of ​​the contact bearing surfaces. Furthermore, the area on which the return spring and the gripping element rest is exposed to contact corrosion or bimetallic corrosion.

[0003] For example, DE102017114260A1 discloses a medical hand instrument in which an integrated return spring is attached to the gripping element via a form fit. However, a disadvantage of this instrument is that a finely milled receiver must be provided on the branch or on the gripping element. Furthermore, due to the provision of an integrated return spring, a high spring force is generated when the hand instrument is closed, which spring force increases linearly. This spring force counteracts, in particular in the closed position, the force applied by a user, such as a surgeon, thus reducing the maximum force that can be applied manually. Furthermore, the spring is subjected to significant deformations, which increases the risk of the return spring breaking during continued use. Summary of the Invention [Means for solving the problem]

[0004] The object and goal of the present disclosure is to avoid or at least reduce the drawbacks of the prior art, in particular to provide a medical instrument, in particular a surgical instrument and a method for manufacturing a medical instrument, which provides good cleanability, is simple and cheap to manufacture, and at the same time maintains a constant force for pivoting the gripping elements over a large range of movement of the instrument, in particular over the entire range of movement. Furthermore, the instrument should in particular be small in size, of simple design, easy to handle and easy to maintain.

[0005] The objectives and aims with regard to the medical device are solved by the features of claim 1 and the objectives and aims with regard to the method for manufacturing the medical device are solved by the features of claim 9.

[0006] The present disclosure therefore relates to a medical instrument having two gripping elements (handle bars, handle levers, lever arms) that are pivotable relative to one another and a spring unit arranged between the gripping elements. Preferably, the U-shaped or V-shaped spring unit has two (spring) ends. Each of the two spring ends is attached to a corresponding / associated one of the two gripping elements, so that when at least one of the two gripping elements is pivoted from a basic state, a pivoting back to this basic state is achieved. This means that when one of the two gripping elements is manually pivoted by a user of the instrument, the spring unit can pivot the pivoted gripping element back to its basic state as soon as the user releases the pivoted handle portion. Preferably, the instrument has a load arm opposite the hinge that pivotally connects the gripping elements. The medical instrument may be configured such that both gripping elements pivot when the instrument is in use. If only one gripping element is intended to rotate, the other gripping element serves only as a counter support for the user's hand during rotation. In particular, the medical instrument has a distal effective part, such as a clamping part (clamping / gripping branch) or a cutting part (cutting blade), which is actuatable via the proximal gripping part.

[0007] According to the present disclosure, such a spring unit is therefore provided in the instrument, in particular extending from at least one of the two spring ends, particularly preferably from both spring ends, towards a bearing, in particular a joint, particularly preferably a hinge or pivot axis, of the gripping element and configured to provide a constant / unchanging force / spring force / restoring force when the gripping element is pivoted, in particular throughout the entire closing movement (all possible pivoting movement) of the instrument. Preferably, in order to achieve a non-varying spring force, a spring unit having at least two parts is provided in the instrument, which spring unit has at least a first spring part, in particular a first spring leg, and a (separate) second spring part, in particular a second spring leg, which spring parts are connected to each other in an at least partially movable manner, in particular coupled to each other. When the two legs or gripping elements are pressed against each other from the base state, the spring force of the spring unit (when pivoting to the closed position) can be maintained uniform and homogeneous, in particular over the entire range of movement of the closing action. The spring force does not increase linearly. This special design supports the user of the device and ultimately increases the maximum potentially applicable closing force, counteracting user fatigue.

[0008] Furthermore, the spring units or spring ends are connected to the grip element in a specially adapted manner. In particular, at least one spring end is form-fittingly inserted into an associated geometrical receiver / recess formed in the grip element and / or is firmly glued to the associated grip element. By inserting the spring end into the recess, the spring end is geometrically fixed in at least one direction (and in particular in the opposite direction) relative to the grip element by form-fitting or undercutting (and in particular by rotation). This locks at least one, in particular at least two possible degrees of movement freedom (out of a total of six, i.e. three translational and three rotational degrees of freedom) of the spring end relative to the associated grip element, in particular in one direction of the longitudinal axis of the grip element and in particular in rotation about an axis of rotation perpendicular to the longitudinal handle axis and perpendicular to the longitudinal axis of the spring end.

[0009] This design allows for a simple, cost-effective construction of the medical instrument, easy cleaning and sterilization, and meets the high demands of medical products. In particular, the spring unit is attached to the gripping element in a non-detachable / loss-proof manner. In particular, the spring unit is in contact with the associated gripping element only at at least one spring end in all pivot positions, in particular in the basic state, so that a well-defined connection point of the spring end and the gripping element, in particular a receiver / recess, allows an individually adapted geometrical design. Good cleaning is guaranteed if the spring end is firmly bonded to the gripping element in such a way that a closed surface is formed at the connection. In particular, in the recess, at least one of the two spring ends protrudes into the recess and is firmly bonded to the gripping element, so that the gap formed between the recess and the spring end is hermetically sealed against the instrument environment in order to prevent the development of bacteria.

[0010] In other words, the spring unit, in particular the spring legs and the at least one gripping element, are configured such that the spring ends are inserted into the gripping element or the branch and / or are firmly bonded, in particular such that no dirt can penetrate or adhere to the interface, e.g. a gap. In particular, at least one of the two spring legs is inserted into the branch and further firmly bonded such that there is a hermetically sealed surface at the connection point without undercuts. Buckling is also prevented when the spring ends are inserted into the associated recesses.

[0011] Thus, the spring unit and the gripping element can be constructed separately, can be manufactured cost-effectively and are reliably connected to one another upon installation.

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

[0013] In further other words, at least one of the two spring ends protrudes into a corresponding, in particular a complementary recess (as a receiver) formed in the associated gripping element, in particular forming at least one undercut in the distal direction along the longitudinal handle axis and / or is firmly bonded to the associated gripping element, in particular in such a way that the gap between the recess and the spring end is hermetically sealed against the instrument environment.

[0014] The term home state defines the position of the pivotable gripping elements relative to each other, to which they are moved solely by the spring unit without any external (manual) forces. In particular, this home state may be the (geometrically determined) maximum open position of the instrument.

[0015] Preferably, the spring unit extends from at least one spring end towards the pivot axis or bearing of the medical instrument, in particular distally. In particular, at least one spring extends from its spring end towards the pivot axis or bearing, preferably distally. In other words, the spring unit, in particular at least two springs, may be arranged between two rotatable gripping elements and may extend along these gripping elements towards the pivot axis or bearing, in particular the hinge. Thus, the spring unit or spring does not protrude proximally or away from the bearing. This allows for a more efficient use of installation space and further improves ergonomics. The surgeon does not have to be careful that the spring unit does not inadvertently catch on external objects such as surgical drapes or inadvertently damage external objects such as tissue. The spring unit is, in particular, arranged between the gripping elements or between the gripping elements (at a height similar to the longitudinal axis of the instrument) and in a sense is surrounded by the gripping elements, which protect the spring unit from the outside (laterally).

[0016] In particular, the recess may be provided on the inside of the associated grip element (i.e. facing the other grip element) and / or the longitudinal axis of the recess may point towards the opposite grip element. The recess opens laterally on the inside and the spring end is inserted therein, so that the spring unit is held in a loss-proof manner and the spring force can be transmitted particularly well to the grip element. For this reason, the recess is formed on the inside of the grip element, not at the proximal end of the grip element. In particular, this optimizes the installation space and the arrangement of the spring unit in cooperation with the spring unit.

[0017] Advantageous embodiments are set forth in the dependent claims and are explained in detail below.

[0018] According to one aspect of the disclosure, at least one spring end and the associated gripping element may be welded and / or soldered, in particular brazed with additives and / or glued, in particular at the contact area / contact boundary between the outer surface of the spring end and the inner surface of the associated gripping element facing the other gripping element. These strongly glued connections are durable and easy to make, in particular in the case of circumferential welded or soldered seams, and represent a hermetically sealed boundary from the environment, which cannot be penetrated by contaminants and can be sterilized even at high temperatures.

[0019] According to a further aspect of the disclosure, at least one of the two spring legs may in particular have a cantilever angle between the protruding spring end and the associated gripping element (distal to the spring end, as viewed in the longitudinal axis of the branch) of at least 30°, preferably at least 45°, most preferably at least 70°, in particular exactly 90°. The cantilever angle may also be said to define the angle between the longitudinal axis of the gripping element and the longitudinal axis of the spring end. This minimum cantilever angle ensures that a gap of sufficient obtuseness is formed to allow easy cleaning.

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

[0021] Preferably, at least one spring leg may be configured as a leaf spring or spring steel wire, in particular having as material X20CR13 or material 1.4021 according to DIN EN 10088 or being entirely made of this material. If the spring leg or the entire spring unit is made of this material, very good mechanical properties, very good abrasiveness, good chemical resistance and good forgeability with satisfactory weldability are provided.

[0022] According to one embodiment, the spring unit may be composed of two parts in the form of two leaf springs or two spring steel wires, which are connected / coupled to each other via a distal spring connection, in particular via a distal fork-nose connection or a distal sphere-pan connection or a distal Yt connection. Leaf springs are simple and cheap to manufacture, can be easily and irreversibly bent to the desired shape and can provide a reliable spring force. On the other hand, spring steel wires are also cheap and meet the requirements of mechanical properties for corresponding shaping. In particular, they are particularly easy to clean, since they have a circular cross section and therefore no corners. In the two-part form with a distal spring connection, the spring force remains constant over the entire closed path of the instrument or when the gripping elements are rotated relative to each other in any rotational position. As with the one-piece spring unit, a linear increase in the spring force is avoided.

[0023] According to a further embodiment, in the case of a spring unit consisting of at least two parts, at least one of the two spring legs, in particular both spring legs, may be S-shaped, in particular with a first proximal bending radius and / or an opposing second distal bending radius, preferably the curve angle / bending angle between the tangent parts of the proximal bending radius (or of the partially circular segment) is 90° and / or the distal bending radius is 45°. The S-shaped design supports the spring elasticity and the geometrical change or approximation of the spring legs relative to the gripping element, in particular such that the spring legs do not come into contact or abut with the gripping element in any pivot position or at least in the basic state of the gripping elements relative to each other.

[0024] In particular, the recess may be a blind hole or a groove or a slit, in particular a passage-like slit. A spring steel wire of (generally) the same diameter (press-fit or clearance-fit, similar to a pin threaded through a hole) may be inserted into a blind hole of a certain predefined diameter. If a leaf spring is used as spring leg, a leaf-shaped / plate-shaped spring end (with a relatively smaller height than width) may be inserted into the elongated groove. For example, if it is a continuous groove, the leaf spring may not be inserted along its longitudinal axis, but along the transverse direction of the groove. The groove may also have an undercut in the insertion direction and the spring end may have an associated protrusion such that, when inserted transversely, a form-fit is formed in the direction of the longitudinal axis of the spring end. Furthermore, the recess may have a depth (in the direction of the longitudinal axis of the protruding spring end) of at least 2 mm and / or at most 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 may be adapted to the gripping element such that the first and / or second spring leg contacts the associated gripping element only at the spring end as connection point, at least in the base state, in particular in all positions in which the gripping elements are rotated relative to one another, thereby preventing wear and increasing the durability of both the spring unit and the gripping element.

[0026] Preferably, the spring units may have distal spring connections attached so as to be releasably displaceable and / or pivotable relative to one another.

[0027] Preferably, the recess and / or the spring end are angular or elliptical (not circular) in shape, such that any degree of rotation about the longitudinal axis of the spring end is prevented. In particular, the spring end and the recess have a shape such that only one single geometric degree of freedom remains in one direction, which is further preferably acted upon, for example by a pretensioning force by the spring unit, in order to hold the spring unit in a loss-proof manner. Alternatively or additionally, the spring end may also be firmly bonded to the gripping element.

[0028] Preferably, the medical instrument may be configured as a multi-joint bifurcated forceps. In particular, the medical instrument may be configured as a multi-acting, in particular double-acting forceps, particularly preferably as a double-acting rongeur. The spring structure disclosed herein is particularly suitable for this type of instrument. Such instrument-type multi-acting or double-acting forceps, in particular rongeurs, have several joints, which are particularly stable. However, the joints also result in a higher total internal friction (multiple joints provide a larger friction surface), which requires a larger spring (unit) restoring force. This is different from the requirements for the return spring of nerve scissors or forceps. In instrument-type double-acting forceps, the spring force is already very high at the beginning of the closing process, so that it is particularly disadvantageous if the spring force increases during the closing process. In particular, double-acting rongeurs are used to cut out parts of bone, an operation that requires considerable force in itself, so that the hand force required by the user to close the double-acting forceps is a particularly large obstacle. It is particularly advantageous for these double-acting rongeurs that the recesses or receivers of the gripping elements extend at an angle towards the bearing, in particular the joint or the pivot axis, since this configuration reliably prevents the spring ends from slipping out under high spring forces. In contrast, perpendicular receivers or recesses, i.e. receivers that extend perpendicular to the longitudinal axis of the associated gripping element or towards the user, are particularly prone to being pushed out of the recesses or receivers when high forces are applied, rendering the instrument unusable and also compromising the safety of the patient.

[0029] The objectives and goals of the present disclosure with respect to a medical device with a spring unit, in particular a method for manufacturing the device of the present disclosure, are solved in particular by the following steps in this order: bending at least one spring leg, in particular a leaf spring or a spring steel wire; forming the distal part of the spring leg, in particular by pressing and / or grinding, preferably by grinding a radius distally; inserting at least one spring leg into a recess, in particular in the form of a blind hole or a groove, formed in a gripping element; orienting the spring leg, preferably with respect to the associated gripping element; and rigidly joining the spring leg to the associated gripping element, in particular by welding and / or soldering. These steps of the method provide an assembly of a medical device with at least one gripping element and one spring leg, which is easy and cheap to manufacture and easy to clean. The manufacturing, including the simple installation, is easy to carry out and cheap.

[0030] Preferably, after the step of firmly joining, the method may comprise the steps of tempering the spring legs together with the associated gripping elements and / or brushing and / or sandblasting the spring legs together with the associated gripping elements.

[0031] Additionally, the method may include assembling the entire device.

[0032] In other words, a medical instrument can be provided in which, in particular, one for each branch (gripping element), preferably two leaf springs or two spring wires / spring steel wires are inserted and / or welded and / or soldered and / or glued into blind holes or grooves in the branches. Since the spring does not hang anywhere on the branch other than its connection (at least in the basic state), good washability or cleanability is guaranteed. A two-part spring in the concept of a spring in distal contact via a spring force, a fork-nose connection or a sphere-pan connection, in particular in the form of a forceps, has the advantage that the spring force does not increase linearly when closing the medical instrument. As a result, the closing force remains substantially constant.

[0033] The present disclosure will be explained in more detail below based on preferred embodiments with reference to the accompanying drawings. [Brief description of the drawings]

[0034] [Figure 1] FIG. 2 is a top view of the medical instrument of the first preferred embodiment, in which the spring unit is form-fitted and firmly attached to the handle portion. [Diagram 2] 2 is a detailed view of the distal spring connection of the two leaf springs of the spring unit of the medical device of FIG. 1 . [Diagram 3] FIG. 13 is a top view of a medical device according to a further second preferred embodiment, wherein the spring unit has a distal Yt connection. [Figure 4] FIG. 13 is a detailed view of the distal connection of the spring unit of a further preferred embodiment of the device, which is in the form of a sphere pan connection. [Diagram 5] FIG. 13 shows a top view of a spring unit of a further preferred embodiment of the medical device. [Figure 6] FIG. 6 is a top view of a preferred embodiment medical device with the spring unit of FIG. 5 inserted therein; [Figure 7] FIG. 7 is a detailed view of the distal spring connection of the spring unit of FIG. 6 . [Figure 8] 4 is a flow chart of a process for manufacturing a medical device according to a preferred embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] The figures are schematic and are intended only to aid in the understanding of the disclosure. Identical elements are provided with identical reference numbers. Features of different embodiments may be interchanged. Any disclosure related to the method according to the present disclosure applies to the medical device of the present disclosure, as does any disclosure related to the medical device of the present disclosure.

[0036] FIG. 1 shows a partial perspective view of a medical instrument 1 in a basic state of a first preferred embodiment. The instrument 1 in the form of a hand instrument is configured as a bifurcated forceps of the forceps type. For this purpose, the instrument 1 has two levers 2, 4 which are pivotally connected to one another via a hinge 6. This allows the two levers 2, 4 to be pivoted relative to one another in a pivot plane S, similar to a pair of scissors or grasping forceps. The proximal parts of the levers 2, 4 (proximal to the hinge 6, towards the user) form gripping parts 8 with corresponding gripping elements or handles 10, 12, which are substantially symmetrical to one another with respect to the longitudinal instrument axis. The gripping parts 8 are also symmetrical with respect to the pivot plane S.

[0037] Between the first handle 10 and the second handle 12 there is provided a two-part spring unit 14 in the form of a two-part leaf spring which forms a first spring leg 16 and a second spring leg 18 of the spring unit 14 which are releasably coupled to each other at their respective distal ends and are displaceable and rotatable.

[0038] The free spring ends 20, 22 of the spring legs 16, 18 are located in groove-shaped recesses formed in the respective handles 10, 12 on opposing inner surfaces 26, 28 projecting inwardly of the handles 10, 12. The recesses 24 are straight, symmetrical to one another with respect to the longitudinal instrument axis and point slightly obliquely forward in the distal direction (in plan view). The spring ends 20, 22 project into the recesses 24 and thus form a cantilever angle α between the distal outer surface (spring end portion) of the leaf spring, i.e. the surface facing distally, and the inner surface 26 or 28. This also substantially corresponds to the angle between the longitudinal branch axis or longitudinal handle axis along the handles 10, 12 and the spring end 20, 22 or the spring end portion or spring end longitudinal axis adjacent to the spring end 20, 22.

[0039] The spring ends 20, 22 are also firmly bonded or welded to the inner surfaces 26, 28 such that the gaps between the recesses 24 and the respective spring ends are hermetically sealed against the instrument environment, which on the one hand ensures that the spring unit 14 is securely attached or connected to the instrument 1 and on the other hand ensures that there are no gaps or other mass areas which are difficult to access and which may harbor bacteria.

[0040] This special design of the instrument 1 with the form-fitting and strong connection of the spring unit 14 with the handles 10, 12 and the special cantilevered portion of the spring ends 20, 22 from the handles 10, 12 allows a cost-efficient production of the instrument 1, a high mechanical load capacity, a long service life and very good cleanability, in particular sterilizability, since in particular a sufficient distance between the spring legs 16, 18 and the handles is also ensured. Since a cantilever angle α of at least about 45° is selected, a sufficiently obtuse angle is formed between the spring ends 20, 22 and the handles 10, 12, which also facilitates good cleaning. In particular, the form-fit of the recesses 24 with the associated spring ends 10, 12 ensures a sufficient mechanical force of the spring unit 14, so that the instrument 1 is durable and its function is guaranteed even after a very large number of pivoting movements. The parts are prevented from coming loose. In particular, the welded seams ensure a tightness against the environment and also increase the mechanical strength of the connection.

[0041] The two leaf springs are made from 1.4021 material in accordance with DIN EN 10088 and offer very good mechanical properties, excellent polishing resistance with chemical resistance and weldability.

[0042] FIG. 2 shows in detail the distal spring connection 30 of the instrument 1 of FIG. 1 in the form of a distal fork-nose connection, seen from the distal to proximal direction. The free distal end of the first spring leg 16 has a nose 32, which is guided by the longitudinal instrument axis and is longitudinally displaceable and pivotable and is enclosed between two prongs or arms 36 or a fork 34 with side walls. In this way, the distal spring connection 30 can follow the movement of the instrument 1 as it pivots, the spring force remaining constant over the entire pivot path. It is also easy to install. The two distal ends are detachably connected to each other in that the nose 32 and the fork 34 engage and are elastically pressed against each other due to their pretension. To some extent, a spring pretensioned hinge is created at the distal end as the spring connection 30.

[0043] Fig. 3 shows the medical device 1 of a further second preferred embodiment. In contrast to the first embodiment, the spring unit 14 and the associated recess 24 are configured differently. In particular, the two spring legs 16, 18 are configured not as leaf springs but as S-shaped spring steel wires, which are inserted into the recess 24 configured as blind holes. Furthermore, the distal connection 30 is configured as a Yt-shaped connection with a Y-shaped distal end portion / Y-portion 38, which engages and is detachably connected in contact with a t-shaped distal end portion t-portion 40. The Y-portion 38 has a circular cross section in its two parallel Y-arms 42, as does the entire second spring leg 18. The Y-arms 42 converge at a curved branch 44. The t-section 40 has a cross-piece 46 with a circular cross section perpendicular to the longitudinal axis of the first spring leg 16, which to some extent forms a t- or X-shaped section, which is in meshing contact with the Y-section. Both spring legs 16, 18 are pretensioned with respect to each other. In particular, in this embodiment of FIG. 3, the cross-piece 46 is arranged distally with respect to the two Y-arms 42, so that the cross-piece 46 forms a kind of stop for the Y-section 38 in the distal direction. In other words, the spring leg 16 is accommodated proximally of the two cross-pieces 46 between the two Y-arms 42. Due to the pretension, in particular when the two handles 10, 12 are pressed together, the Y-section 38 is pressed in the distal direction, but is prevented by the two cross-pieces 46 which extend transversely with respect to the spring legs 16. On the other hand, since the tee section 40 is held in the fork of the Y section 38, the two spring legs 16, 18 are removably coupled to each other, providing a constant spring force throughout the entire pivot path.

[0044] This embodiment with the Yt connection allows good elastic bending of the two spring legs 16, 18, which are made of spring steel wire and bent (irreversibly) into an S-shape or have such a shape along their longitudinal axis, while at the same time providing a secure (removable) connection at the distal spring link 30. This design is particularly cost-effective to manufacture.

[0045] FIG. 4 is a detailed view of the distal part of the spring unit 14, here the spring connection 30 of a further preferred embodiment. The distal spring connection 30 of FIG. 4 can be used in the instrument 1 instead of the Yt connection of FIG. 3. In contrast to the spring connection 30 of the second embodiment of FIG. 3, the spring connection of FIG. 4 has a sphere-pan connection with a distal sphere 48 formed on the first spring leg 16 and a pan (shallow dish-shaped) 50 formed on the second spring leg 18 instead of the Yt connection. In particular, the sphere 48 is spring pretensioned in a shell-shaped receiver of the pan 50, forming a detachable connection or coupling between the distal ends (against the pretension of the spring unit 14). This special coupling means that when the handles 10, 12 are rotated from the base state, the two spring legs 16, 18 are first pushed distally with freedom of movement and elastically deform. However, because a (spherical) joint is formed by the sphere 48 and the pan 50, the distal ends can move and rotate towards each other, so that the spring force remains uniform or a substantially constant spring force is achieved during a pivoting movement, such as a closing movement in the closing direction.

[0046] FIG. 5 shows a spring unit 14 according to a further preferred design, which is not yet connected to the handle (and is not pretensioned). The spring legs 16, 18 are symmetrical to each other, except for the distal ends. The proximal spring ends 20, 22 have a bend with a first proximal bend radius 60 (specifically radius R6), which is a rightward bend through 90° (as seen in FIG. 5 for the second spring leg 18). After a short straight section (specifically 9 mm long), there follows a leftward bend (as seen in FIG. 5 for the second spring leg 18) around a bend angle β of 45° with a larger distal bend radius 62 (specifically R17, which is generally or just three times larger). This is followed by a straight section, the distal end part of which is slightly bent to the left (specifically about 5°) and has a spherical rounding at the end.

[0047] The first spring leg 16 is S-shaped symmetrically to the second spring leg 18, but has a pan-shaped recess 52 at its distal end, the pan / shell-shaped receiver of which opens towards the second spring leg 18 or towards the distal spherical radius. The spherical distal end of the second spring leg 18 is inserted into this receiver. The maximum dimension 56 in the plane of rotation S perpendicular to the longitudinal instrument axis in the non-pretensioned state is in particular about 1.3 times the maximum dimension in the plane of rotation S in the direction of the longitudinal instrument axis. The dimension 58 of the cantilevered part of the spring end 20 in the plane of rotation S perpendicular to the longitudinal instrument axis is about 20% of the maximum dimension 56. In particular, the dimension 58 of the cantilevered part is 11 mm. In particular, the spring ends 20, 22 have straight portions that extend over approximately one-third or one-half the dimension 58 of the cantilever portion, in particular 5 mm.

[0048] Figures 6 and 7 show a top view and a detailed top view in the region of the distal spring connection 30 of a medical instrument 1 according to a further preferred embodiment. The medical instrument 1 is configured as an articulated bifurcated forceps and has a distal active part 64 in the form of a forceps. The spring unit 14 of Figure 5 is inserted into this instrument. In particular, the two spring ends 20, 22 protrude at the inner surfaces 26, 28 into recesses (not shown) in the handles 10, 12.

[0049] The cantilever angle α is larger than in the first embodiment and is approximately 80°. The proximal bend radius 60 adjoins the spring ends 20, 22 at each section. As a result, a defined gap is provided inside the handles 10, 12, which has a high minimum size and ensures good cleanability due to the rounding of the circular cross section of the S-shaped spring steel wire and the rounding of the bend radius 60. Furthermore, the instrument 1 is easy and cheap to manufacture.

[0050] 8 shows a flow chart of a method for manufacturing the device 1 according to a preferred embodiment. In this embodiment, the method produces the device 1 according to the present disclosure.

[0051] In a first step S1, both the first and second spring legs 16, 18 are bent into the correct shape. In particular, the spring legs 16, 18 are in the form of spring steel wire or leaf springs, and are bent (according to a design drawing) into an S-shape.

[0052] In step S2, the distal portions of the two spring legs 16, 18 are formed, which will later be joined distally. Specifically, the free end of the first spring leg 16 is pressed to form a flattened spoon- or bread-shaped structure / pan 52, thereby forming a cup-shaped receiver. The other distal end of the second spring leg 18 is ground distally to create a spherical radius 54.

[0053] The order of steps S1 and S2 is not critical, and these two steps may be performed in reverse order.

[0054] This is followed by step S3 of inserting the two spring legs 16, 18 into blind hole-like recesses 24 formed in the handles 10, 12 respectively, so that a form-fit connection is formed between the spring legs 16, 18 and the associated handles 10, 12.

[0055] Then, in step S4, the two spring legs 16, 18 are aligned with the associated handles 10, 12. In particular, the distal bulbous radius may already be loosely inserted into the complementary pan 52 at this point, and the two spring legs 16, 18 may be pre-tensioned with respect to each other to ensure correct alignment.

[0056] In this aligned position, the spring legs are firmly bonded in step S5, in this case welded to the associated gripping element, in particular by means of a filler material, in particular by forming a circumferential weld seam on the handle 10, 12 around or at the end portion of the spring ends 20, 22, such that the gap formed between the spring ends 20, 22 and the recess 24 is hermetically sealed.

[0057] After the step S5 of firmly adhesively connecting, a step S6 of tempering the spring legs 16, 18 and the associated gripping elements 10, 12 is performed. In particular, the entire device 1 or all of its components are tempered.

[0058] In step S7, the handles 10, 12 and spring unit 14 are brushed, and in particular the connection points between the handles 10, 12 and the spring legs 16, 18 are sandblasted to provide a smooth surface.

[0059] Finally, following step S8, the overall assembly of the device 1 takes place. [Explanation of symbols]

[0060] 1 Medical equipment 2. First Lever 4. Second Lever 6 Hinge 8 Gripping part 10 First gripping element 12 Second gripping element 14 Spring unit 16 First spring leg 18 Second spring leg 20 first spring end 22 Second spring end 24 Hollow 26 The First Inner Self 28 The Second Inner Self 30 Distal spring connector 32 Nose 34 Fork 36 Fork arm 38 Y section 40t part 42 Y section 44 Y-branch 46 Cross Piece 48 Sphere 50 Bread 52 Dent 54 Bent end 56 Dimensions 58 Cantilever dimensions 60 (First) Proximal Bend Radius 62 (Second) Distal Bend Radius S Rotating surface α Cantilever angle β bending angle S1 Step to bend the spring legs S2: Forming the distal end S3 Step to insert spring legs S4 Orienting the spring legs against the handle S5 Step for strong adhesion and connection S6 Tempering step S7 Brushing Step S8 Installation Steps

Claims

1. A medical device, - two gripping elements having metal as material and mounted pivotably relative to one another via bearings; a spring unit having two spring ends each connected to one of the two gripping elements such that, when at least one of the two gripping elements rotates from a base state, the spring unit is capable of rotating back to the base state via the spring unit; the spring unit extends from at least one of the two spring ends towards the bearing and is configured to provide a substantially constant spring force when the gripping element rotates; At least one of the two spring ends protrudes into a recess formed in the associated grip element and is firmly attached to the associated grip element.

2. 10. The medical instrument of claim 1, wherein at least one of the spring ends and the associated gripping element are welded and / or soldered and / or glued.

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

4. 10. The medical instrument of claim 1, wherein at least one spring leg is configured as a leaf spring or spring steel wire.

5. the spring unit is made up of two parts in the form of two leaf springs or two spring steel wires, The medical instrument of claim 4 , wherein the two portions are releasably connected to one another via a distal spring connection.

6. 2. The medical instrument of claim 1, wherein at least one of the two spring legs is S-shaped with a proximal bend radius and / or an opposing distal bend radius.

7. The medical device of claim 1 , wherein the recess is a blind hole, a groove, or a slit.

8. 2. The medical instrument of claim 1, wherein the spring unit is configured with respect to the grip element such that, at least in the base state, the spring unit contacts the associated grip element only at the spring end as a connection point.

9. A method for manufacturing a medical device with a spring unit, in particular a device according to claim 1, comprising the steps of: bending at least one spring leg; forming a distal portion or end of the spring leg; inserting the at least one spring leg into a recess formed in a gripping element; and c) adhesively connecting the spring legs to the associated gripping elements.

10. tempering the spring legs together with the associated gripping elements after the step of firmly bonding and connecting, 10. The method of claim 9, further comprising the steps of: and / or brushing and / or sandblasting the spring legs together with the associated gripping elements.

11. 10. The medical instrument of claim 1, wherein the at least one spring end is rigidly bonded to the associated grip element such that a gap between the recess and the spring end is hermetically sealed to the instrument environment.

12. 3. The medical instrument of claim 2, wherein the at least one spring end and the associated gripping element are welded and / or soldered and / or glued at a contact area between an outer surface of the spring end and an inner surface of the associated gripping element facing the other gripping element.

13. 5. The medical device according to claim 4, wherein the at least one spring leg has as material the material X20CR13 or the material 1.4021 according to DIN EN 10088.

14. 6. The medical instrument of claim 5, wherein the two parts of the spring unit are detachably connected to each other via a distal fork nose connection or a distal sphere pan connection or a distal Yt connection as the distal spring connection.

15. 7. The medical device of claim 6, wherein the bend angle between tangent portions of the proximal bend radius is 90 degrees and / or the distal bend radius is 45 degrees.

16. 10. The method according to claim 9, further comprising, after the inserting step, orienting the spring legs relative to the associated gripping elements with an extension of the inserted end of the spring legs towards a bearing, preferably a joint, of the medical instrument, via which the gripping elements are rotatably mounted relative to one another.

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