Method for joining two components of a medical instrument, use of an iron-based solder, and medical instrument

Abstract

A method is provided for joining at least two components of a medical instrument, the at least two components are held so as to form at least one soldering gap between mutually assigned joining areas of the components, a solder material is arranged for filling the at least one soldering gap, and the arrangement of the at least two components and of the solder material is heated to a soldering temperature of the solder material, wherein the solder material is an iron-based solder. A use of an iron-based solder and a medical instrument, in particular a laryngoscope spatula, are also provided.

Claims

1. A medical instrument comprising: at least two components having joining areas, the joining areas of the at least two components being spaced apart from one another such that at least one soldering gap is provided between the joining areas, wherein a solder material fills the at least one soldering gap due to heating of the solder material to a soldering temperature, such that at least one soldering seam is formed, wherein the solder material is an iron-based solder, and wherein the at least two components are laser-welded together prior to the solder material filling the at least one soldering gap, such that the at least two components have a laser weld connection and a solder connection.

2. The medical instrument according to claim 1, wherein the medical instrument is a laryngoscope spatula having a base blade and a cover blade that form an elongate cavity that is delimited in a fluid-tight manner by the at least one soldering seam formed by the solder material.

3. The medical instrument according to claim 1, wherein the medical instrument is a laryngoscope spatula.

4. The medical instrument according to claim 1, wherein the solder material is arranged in a pasty form.

5. The medical instrument according to claim 1, wherein the at least one soldering seam is an overwelded soldering seam that is smoothed.

6. The medical instrument according to claim 1, wherein prior to the solder material filling the at least one soldering gap, the solder material is arranged adjacent to the at least one soldering gap.

7. The medical instrument according to claim 1, wherein the medical instrument is an invasive medical instrument.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein:

(2) FIG. 1 shows a laryngoscope spatula according to an illustrative embodiment of the invention, in an oblique view;

(3) FIG. 2 shows the laryngoscope spatula according to FIG. 1 in a lengthwise view;

(4) FIGS. 3a and 3b show a cross section through the laryngoscope spatula according to FIGS. 1 and 2 before and after the soldering process is carried out.

DETAILED DESCRIPTION

(5) In FIGS. 1 and 2, a laryngoscope spatula 1 according to an illustrative embodiment of the invention is shown in an oblique view and a side view, respectively. The laryngoscope spatula 1 comprises four components, which are connected to one another in a method according to the invention, namely a base blade 2, a cover blade 3, a bead 4, and a spatula head 5. A handle (not shown in the figures) can be attached to the spatula head 5 arranged at the user (proximal) end 6 of the laryngoscope spatula 1, with which handle the laryngoscope spatula 1 can be held during an examination. The laryngoscope spatula 1 can be inserted into the oropharyngeal space of a patient and, for this purpose, has a flattened, curved shape adapted to the anatomical circumstances of the oropharyngeal space. The bead 4 arranged at the distal end 7 of the laryngoscope spatula 1, i.e. the end remote from the user, permits easy and atraumatic insertion.

(6) The base blade 2 has a lower limb 8, which extends in the longitudinal direction of the laryngoscope spatula 1 and which has a flat, curved underside and a similar upper face. The lower limb 8 is adjoined in the transverse direction by a middle limb 9, which is at an angle to the lower limb 8 and which is in turn adjoined by an upper limb 10 which, seen in the transverse direction, extends substantially parallel to the lower limb 8. In sections, the middle limb 9 stands approximately perpendicular to the lower limb 8 and the upper limb 10. The height of the middle limb 9 decreases overall from the proximal end 6 to the distal end 7, wherein the height of the middle limb 9 reaches a maximum near the proximal end 6 and returns to zero near the distal end 7. Thus, in the area of the proximal end 6 of the laryngoscope spatula 1 and over the greater part of its longitudinal extent, the base blade has an approximately Z-shaped cross section and, in the area of the distal end 7 of the laryngoscope spatula 1, merges into a flat cross-sectional shape. The base blade 2 is formed in one piece and is made of stainless steel.

(7) The cover blade 3 of the laryngoscope spatula 1 comprises a first limb 11, which extends in the longitudinal direction of the laryngoscope spatula 1 and stands approximately perpendicular to the upper face of the lower limb 8 of the base blade 2. The lower edge 12 of the first limb 11 is adapted to the shape of the upper face of the lower limb 8 of the base blade 2. In its upper area, the first limb 11 is adjoined, approximately perpendicularly thereto, by a second limb 13, of which the upper face merges into the upper face of the upper limb 10 of the base blade 2 and forms therewith a substantially continuous curved surface. The side edge 14 of the second limb 13 is for this purpose adapted to the profile of the transition between the middle limb 9 and the upper limb 10 of the base blade 2. The cover blade 3 has an approximately L-shaped cross section, wherein the height of the first limb 11 reaches a maximum near the distal end 6 of the laryngoscope spatula 1 and decreases in the distal direction.

(8) The atraumatic bead 4 is attached to the distal end of the base blade 2, wherein the lower limb 8 of the base blade 2 protrudes into a groove 15 of the bead 4. The spatula head 5 is hollow and has coupling elements for a releasable mechanical connection to the handle (not shown). The cover blade 3, the bead 4 and the spatula head 5 are also each formed in one piece and produced from stainless steel.

(9) The cover blade 3 encloses, with the base blade 2, an elongate cavity 16 (see FIGS. 3a and 3b) which, at the distal end, terminates in an opening 17. At the proximal end 6, the cavity 16 is closed off in a fluid-tight manner by a transverse wall formed integrally with the cover blade 3, but communicates (not shown in the figures) with the interior of the hollow spatula head 5 via an aperture of the base blade 2.

(10) In FIGS. 3a and 3b, the laryngoscope spatula is shown in cross section, the cross-sectional view being approximately at the center of the laryngoscope spatula 1, i.e. the laryngoscope spatula 1 is cross-sectioned approximately half way along its length. FIGS. 3a and 3b show the cavity 16 which is formed between the base blade 2 and the cover blade 3 and which serves to accommodate optical and/or electronic structural elements. The cover blade 3 has joining areas, which are formed by the lower edge 12 and the side edge 14. A partial area of the upper face of the lower limb 8 and the transition from the middle limb 9 into the upper limb 10 constitute the joining areas of the base blade 2, which cooperate with the joining areas of the cover blade 3 in order to form soldering gaps 18, 19 in which soldering seams 20, 21 are generated so as to firmly connect the cover blade 3 to the base blade 2 (see FIG. 3b). This is described in more detail below.

(11) According to an illustrative embodiment of the method according to the invention, the laryngoscope spatula 1 is produced by first of all making available the base blade 2, the cover blade 3, the bead 4 and the spatula head 5. These are then connected to one another by laser spot welding in such a way that they are arranged in the manner shown in the figures, but without yet being connected by soldering seams, and instead each forming a soldering gap 18, 19 between one another. In the next step, a solder material 22, namely iron-based solder in pasty form, is introduced by means of a curved syringe needle through the opening 17 into the cavity 16, in each case using a dosing device to provide an amount necessary to create a soldering seam, and applied to the inner faces of the base blade 2 and of the cover blade 3 adjoining the soldering gaps 18, 19 (see FIG. 3a). For example, the iron-based solder ML 7813/S from Innobraze (Esslingen, Germany) is suitable for this purpose. The solder material 22 in each case forms a bead which adjoins the respective soldering gap 18, 19 from the inside and which bears on the inner walls of both components that between them form the respective soldering gap 18, 19. Likewise, the iron-based solder is introduced into the groove 15 and into the spatula head 5 adjacent to a soldering gap formed between the spatula head 5 and the underside of the base blade 2. For this purpose, for example, a quantity of 0.8 g to 0.9 g is needed for the soldering seams 20, 21 that connect the base blade 2 and the cover blade 3 to each other, and a quantity of 0.5 g to 0.6 g is needed for the soldering seam 24 of the spatula head 5.

(12) This solder bond is then introduced into a furnace and heated to a soldering temperature of approximately 1120° C. The iron-based solider thus liquefies and flows, on account of the capillary action, into the soldering gaps 18, 19 formed between the components to be connected to each other. During the subsequent cooling, which can take place over the course of an hour or a few hours, the iron-based solder hardens in the soldering gaps 18, 19 and forms the soldering seams 20, 21, in order thereby to create a firm, durable and tight connection between the components to be connected to one another. The soldering seams 23, 24 connecting the distal bead 4 and the spatula head 5, respectively, to the base blade 2 are obtained in the same work step. Once cooling is complete, the upper soldering seam 21 between the second limb 13 of the cover blade 3 and the transition from the middle limb 9 to the upper limb 11 of the base blade 2 is overwelded again, in order to increase the strength of the connection, and is then smoothed.

(13) The resulting structure is provided with further components in further steps of the production of the laryngoscope spatula. In particular, optical and electronic structural elements are inserted into the cavity 16. Thus, optical waveguides are inserted into the cavity 16 so that illumination light generated by means of an external light source is conveyed to the distal opening 17 of the cavity 16, or electrical lines are inserted to power a light source arranged in the area of the opening 17. In the area of the opening 17, a viewing lens and an electronic image recorder can be inserted into the cavity 16. Moreover, electrical lines for powering the electronic image recorder and for transmitting signals can be inserted into the cavity 16, likewise an image conductor for forwarding a recorded image. The optical waveguides and/or electrical lines are inserted proximally through an opening (not shown in the figures) of the base blade 2 into the spatula head 5, into which coupling elements are inserted for attachment to corresponding optical waveguides or electrical lines extending inside the handle. By way of these lines, the electronic elements are supplied with electrical energy and the recorded image of the oropharyngeal space of the patient is conveyed to an external display device.

(14) The opening 17 can be closed, for example, by a transparent window or by a video module which contains the viewing lens and the electronic image recorder. The passage between the cavity 16 and the spatula head 5 is likewise closed in a vapor-tight manner at the proximal end. Since the soldering seams are smooth and vapor-tight, the optical and electronic structural elements arranged in the cavity 16 are protected against entry of vapor during autoclaving.

(15) The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.