HU204427B - Round head for hip-joint endrorotheses and method for producing the round head - Google Patents

Abstract

Spherical head for hip joint endoprosthesis comprising a hollow spherical segment and a sleeve or transition piece adjoining the neck part of the stem to be fastened on the femoral bone. In order to achieve as low a weight as possible the spherical segment is made from deep-drawn sheet metal and fastened on the adjoining sleeve by a welded join.

Description

BACKGROUND OF THE INVENTION The present invention relates to a spherical head for hip joint endoprosthesis consisting of a hollow spherical segment and a sheath attached to the neck portion of a shank to be secured to the femur. A special group of artificial hip joints is called the so-called. “Cervicocapital” joints in which the femur is attached to a spherical head that, after surgical implantation, performs the functions required to fit the natural pelvis of the pelvis. In the artificial hip joint disclosed in HU 190563, the diameters of these spherical heads are anatomically dimensioned and meet all the biological, chemical, and physical requirements required by international standards and are subject to extensive quality testing.

Currently, such prostheses are manufactured mainly in small series with solid machining. However, these compact ball-shaped heads are quite heavy and / or bulky and, after being incorporated, are subject to an additional 20 loads.

Cast or welded hollow spherical heads are also known, which are mainly used in medium and large series production. Although much lighter than solid spherical heads, they are significantly more expensive to manufacture and have problems with their use. The sliding surface of the hollow spherical heads is not completely porous due to the casting technology. The quality and slip properties of the working surface are less favorable than those of solid spherical heads due to the micro-cracks and burrs found during machining.

Therefore, the present invention aims to provide a spherical head for hip joint endoprostheses which, due to its hollow design, is lightweight and thus has favorable application properties, yet is not complicated and costly to manufacture and has a surface of the same quality as solid spherical heads.

The object is solved by the deep segment of the spherical segment and the spherical head plate being deep-drawn and welded to the connecting sleeve by means of a ball head consisting of a spherical spherical segment and a sheath attached to the neck portion of the shank.

Preferably, the connecting sleeve itself is formed of a deep-drawn plate 45.

In the process of making the spherical head according to the invention, the disk is first cut out of a plate, then the disk is deep-drawn into a hemispherical cylindrical shape, then the cylindrical part is narrowed, melted and welded to the connecting sleeve after calibration.

The coupling sleeve can be made in a similar manner: first, a disk is cut from the plate and then deep-drawn and machined into a coupling sleeve 55.

The spherical segment and the neck portion are preferably joined by electron beam or laser welding.

The endoprosthesis according to the invention has a surface quality of a spherical head 60 and, consequently, a wetting effect! Its slope and sliding properties are significantly better than those of conventional hollow spherical heads, which further has the advantage of increasing the life of the counterpart, the pool duct.

The disc pre-production is made using highly secure, mature technology. Cold forming guarantees compactness, cracking and excellent strength properties both in sheet and cold-formed products. The hand-designed, designed design increases hardness and abrasion resistance so that it does not cause cracks while developing favorable properties.

Modern technology can be used to produce the product of the invention, but it also reduces manufacturing costs by improving quality: the pre-product weight and cost is reduced by 85-90%, the finished product weight is reduced by about 20% and the product cost is reduced by 70-80%.

Further details of the invention will be illustrated by way of exemplary embodiments, with reference to the drawings. On the drawings it is

Figure 1 is a sectional view of a ball head according to the invention,

Figure 2 is a sectional view of another embodiment of the present invention,

Figure 3 is a sectional view of a further embodiment of the ball head according to the invention, a

FIG. 4 is a first step in the production of a spherical segment technology, FIG

Figure 5 is the second step in the production technology of the sphere segment, a

Figure 6 shows the third step in the production of the spherical segment, while Figure

Figure 7 illustrates the technology for making the coupling sleeve.

1-3. 1 to 4, each has a hollow body formed of a spherical segment plate. In each case, the connecting sleeve 2 is connected to the ball segment 1 by welding seams 3. However, while the forming sleeve 2 in the embodiment shown in Figs. 1 and 2 is also a sheet-shaped unit, in Fig. 3 it is formed as a cast piece.

The technology for producing 1 spherical segment is illustrated in Figures 4-6.

.

As a first step in the process, a disc is cut from a stainless steel plate, and as shown in Figure 4, the disc is drawn in a deep drawing tool 5 into a cylindrical bottom with a hemispherical bottom 4.

The next step of the process is illustrated in Figure 5.

Here, the cylindrical portion is narrowed and inclined as shown in FIG.

Figure 7 shows that the connecting sleeve 2 is similarly deep-drawn in a tool 5.

After joining the 2 connecting sleeves and 1 spherical segments, the working and fitting surfaces

HU 204427 Β Finish turning, grinding and polishing.

Of course, the embodiments shown are only a few variations of the embodiments of the present invention, which may be produced in numerous variations within the scope of the appended claims.

Claims (5)

A ball head for hip joint endoprosthesis, comprising a hollow ball segment and a sleeve attached to the neck portion of a shank to be attached to a femur, characterized in that the ball segment (1) is formed of a deep-drawn plate and is welded to the coupling sleeve (2). Spherical head according to claim 1, characterized in that the connecting sleeve (2) is made of a deep-drawn plate. 3. A method for producing a ball head according to claim 1 or 2, characterized in that it is first made of sheet After cutting 5 discs, the disk is deep-drawn into a hemispherical cylindrical shape (4), then the cylindrical part is narrowed, then cast and the resulting spherical segment (1) is welded to the coupling sleeve (2). 10 Method according to Claim 3, characterized in that the coupling sleeve (2) is manufactured by first cutting a disc from a sheet and then forming it by drawing and cutting. Method according to Claim 3 or 4, characterized in that the coupling of the spherical segment (1) and the coupling sleeve (2) is carried out by electron beam or laser welding.