Bent tubular shaft and method for producing the same

Abstract

The disclosed embodiments describe a method for producing a bent tubular shaft for a tubular shaft instrument as well as a tubular shaft produced in such manner as well as a tubular shaft instrument with such a bent tubular shaft. The tubular shaft is produced by providing a hollow shaft component and an actuating rod. The actuating rod in this case has at least one bending area in which flexible segments and support segments alternate. The at least one bending area of the actuating rod is provided with a friction-reducing layer before it is inserted into the shaft component in order to create a tubular shaft. The tubular shaft is then bent in an area that corresponds to the at least one bending area of the actuating rod.

Claims

1. A method for producing a bent tubular shaft for a tubular shaft instrument comprising: providing a hollow shaft component, providing an actuating rod, wherein the actuating rod has at least one bending area in which flexible segments and support segments alternate, providing the at least one bending area of the actuating rod with a friction-reducing layer, inserting the actuating rod into the hollow shaft component in order to create a tubular shaft, and bending of the tubular shaft in an area that corresponds to the at least one bending area of the actuating rod, including grasping the tubular shaft in an area located outside the at least one bending area of the actuating rod, wherein the at least one bending area of the actuating rod is produced, in which flexible segments are formed on a cylindrical rod by removing material from the rod, and support elements are formed, in which the original diameter of the cylindrical rod is essentially retained in at least one transverse direction at these sections, and wherein the flexible segments are formed as cylindrical sections having a smaller cross-sectional area than the rod outside the at least one bending area, and wherein the support segments are formed essentially spherical and have a maximum diameter that essentially corresponds to the diameter of the cylindrical rod outside the at least one bending area, wherein two adjacent support segments are connected by a flexible section.

2. The method for producing a bent tubular shaft according to claim 1, wherein before the step of bending the tubular shaft functional elements are attached to the distal ends of the hollow shaft component and the actuating rod.

3. The method for producing a bent tubular shaft according to claim 1, wherein providing the at least one bending area of the actuating rod with a friction-reducing layer comprises: pulling a shrink tubing over the at least one bending area of the actuating rod; and shrinking the shrink tubing at the at least one bending area of the actuating rod.

4. The method for producing a bent tubular shaft for a tubular shaft instrument according to claim 1, wherein the at least one bending area of the actuating rod does not extend up to one of the two axial ends thereof.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows an isometric view of a tubular shaft according to an exemplary embodiment;

(2) FIGS. 2A-C show isometric views of an actuating rod of a tubular shaft according to the exemplary embodiment in FIG. 1 in the unbent condition;

(3) FIGS. 3A-C show isometric views of a shaft sleeve of a tubular shaft according to the exemplary embodiment in FIG. 1 in the unbent condition; and

(4) FIGS. 4A-B show isometric views of an actuating rod of a tubular shaft according to the exemplary embodiment in FIG. 1 in the bent condition.

DETAILED DESCRIPTION OF THE DISCLOSED EMBODIMENTS

(5) An exemplary embodiment of the disclosed subject matter is described in detail in the following with reference being made to the figures.

(6) A tubular shaft 1 according to this exemplary embodiment has two bent areas or bending areas, 2 and 3, as well as a straight area 4. At the distal end of the tubular shaft 1 are functional parts 11, 12, which are rotatably attached by an axle 13 at the bars 14, which are formed at the distal end of the shaft component 20. In this exemplary embodiment, the functional parts 11, 12 together form shears. At the proximal end of the tubular shaft 1, a coupling is formed with which the tubular shaft may be detachably mounted onto the handle component. The tubular shaft 1 with this exemplary embodiment is designed as a disposable article that can be mounted onto a reusable handle part (not shown). The shaft sleeve 20 has ball adapters 15 for coupling, into which the balls insert as securing elements in order to retain the shaft sleeve 20 on the handle part. The actuating rod 30 has a coupling ball 16 on its proximal end that may be detachably coupled to a corresponding adapter on the handle part in order to transfer an actuation of the actuating element of the handle part to the actuating rod 30 and thus ensure function of the functional parts 14.

(7) In the bending areas 32, 33 of the actuating rod 30, flexible segments 34 and support segments 35 alternate, and the actuating rod 30 has significantly lower bending resistance than in the straight area 31 outside of the two bending areas 32, 33. In this exemplary embodiment the bending areas 32, 33 have the approximate appearance of a string of pearls. A shrink tube (not shown in the figures) is arranged at the two bending areas 32, 33 of the actuating rod 30 as a friction-reducing layer. The shrink tube pieces also serve as a compensating layer for deformations that result during the bending process of the tubular shaft 1 at the actuating rod 30 but also particularly at the shaft sleeve 20. The shrink tube is made of plastic and has a lower elasticity modulus than the actuating rod 30 and the shaft sleeve 20, which are produced from a titanium alloy.

(8) The actuating rod 30, i.e. the bending areas 32, 33 of the same, is/are milled from a cylindrical rod and are therefore formed as a single piece. In the straight area 31, the actuating rod 30 is essentially to be considered rigid with respect to the forces occurring during the bending process and proper use. At the distal end of the actuating rod 30, a sliding component 36 is provided having two guide tracks with a cam protruding into each that is provided on the proximal end of each functional elements 11, 12 and inserts into the slide element. Advantageously, the sliding component 36 is axially rotatable in relation to the actuating rod 30 not only in this exemplary embodiment, which means that during insertion of the actuating rod 30 into the shaft sleeve 20, attention does not have to be paid to the alignment of the actuating rod 30.

(9) For the assembly of the tubular shaft 1 according to this exemplary embodiment, two pieces of shrink tubing (not shown) are pushed over the two bending areas 32, 33 of the actuating rod 30 and shrunk through heating. The proximal end of the actuating rod 30 is then inserted into the opening on the distal end of the shaft sleeve 20 and pushed into the shaft sleeve 20 until only the sliding element 36 is protruding at the front (distally) from the shaft sleeve 20. The cams of the functional parts 11, 12 are then threaded into the guide tracks, and the actuating rod 30 is then pushed a bit further into the shaft sleeve 20 until the bearing holes of the functional parts align with the bearing holes in the bars 14 of the shaft component. A bearing axle is then pushed through the bearing holes of the bars 14 and the functional parts 11, 12 and affixed to the bars 14. Finally, the tubular shaft 1 assembled in this manner is bent at the points at which the bending areas 32, 33 of the actuating rod 30 are arranged on the interior of the shaft sleeve 20 and the tubular shaft 1 is placed into the desired shape in this manner.

(10) According to further exemplary embodiments of the disclosed subject matter, the friction-reducing layer may also consist of or include a coating, put-on half shells or partial shells and/or an injection molded material. The friction-reducing layer may either be provided only at the bending areas 32, 33 or over the entire length of the actuating rod 30. It is also possible for the friction-reducing layer to be provided at the bending areas 32, 33 only at the spacers, since the flexible segments do not come into contact with the shaft sleeve and compensation of the deformations at the flexible segments is not required.

(11) The bending areas may also be formed in a different manner. The uniform string-of-pearls shape previously shown can be modified to the extent that the support segments have different spacing with respect to one another, that the flexible segments have different cross-sectional areas and/or shapes and/or are arranged outside the longitudinal direction of the actuating rod.

(12) If more than one bending area is provided in an exemplary embodiment, the bends in each bending area may lie in one and the same plane. As an alternative to this, the planes in which the bending in the individual bending areas takes place may be skewed with respect to one another. As another alternative, it is also possible for a bending area to be simultaneously bent in multiple spatial directions such that the tubular shaft, for example, takes on a spiral shape in this section.

(13) A person skilled in the art may furthermore combine the described features of the tubular shaft in any suitable manner.