Hydraulic column brake

IS 2 390 127 T3

DESCRIPTION

Hydraulic locking system for one column

The present invention relates to an operating table comprising a table column with a column foot and with a column head, as well as a supporting surface that can be joined or is connected to the column head.

In some operating tables, the support surface is rotatable about the vertical longitudinal axis of the table column to place it in a suitable position according to the need for space or the type of surgical invention to be performed. In such a suitable position the support surface has to be retained with respect to rotation about the vertical axis of the table column.

The possibility of rotating the support surface around the vertical axis of the table column can be achieved for example in such a way that a section of the column foot, located on the side of the column, is rotatably supported on a section of the column foot, located on the ground side, the two sections of the column foot being able to be locked with a mechanical clamping mechanism to retain the position of the support surface.

However, in mechanical clamping mechanisms there is a problem that it is difficult to accurately dimension the clamping force. In mechanical clamping devices in which the clamping force is directly related to the mechanical adjustment of a clamping element, these clamping elements must be mounted with a very small mounting tolerance, since a deviation from the mounting position has an effect directly into the clamping force. Since both too small a clamping force and too strong a clamping force must be avoided in any way, mechanical clamping devices have to be manufactured with great precision and at the high expense that this entails.

The invention has the object of providing an operating table of the type mentioned at the beginning, which allows the support surface to be retained with simple means with respect to a rotation about the longitudinal axis of the table column.

This objective is achieved because the column foot has a bottom plate and a foot plate located on the side of the column, because the foot plate is rotatably mounted on the bottom plate and is secured with a vertical play by means of a counter support that prevents it from being lifted from the bottom plate, and in that at least one pressure-actuated locking cylinder is provided to tension the foot plate against the counter support.

In the operating table according to the invention, the clamping force is applied by a pressure-actuated clamping cylinder. Therefore, this clamping force is adjusted through the pressure of the hydraulic fluid in the locking cylinder and not through the sizing of a mechanical lift stroke or the like, so that the clamping force can be easily adjusted already nevertheless precise, without the need for too high requirements in terms of mounting tolerance. In addition, there are greater freedoms for the construction of the column base, because the hydraulic fluid can be guided through suitable conduits, along any desired path, so that, unlike for example a mechanical shaft, conduits of this type do not pose any obstacle. for the other components of the column foot.

Preferably, the locking cylinder is arranged on the foot plate and, when loaded by the hydraulic means, rests on the bottom plate.

In an advantageous variant, the counter support is formed by a circular ring which is connected to the bottom plate and which surrounds the foot plate, gripping it from above, at least in part, at its outer edge.

Preferably, the at least one locking cylinder can be charged with the hydraulic fluid via a foot-operated pump. By means of a foot-operated pump of this type, a sufficiently high clamping force can be established by investing little force.

According to a particularly advantageous variant, the line between the pump and the locking cylinder is connected to a reservoir for the hydraulic fluid via a pressure limiting valve. In this way, it is ensured that, regardless of the intensity of actuation of the pump, the pressure of the hydraulic fluid introduced into the locking cylinder does not exceed a maximum pressure set by the pressure limiting valve. In this way, overloading of the clamping mechanism cannot occur and it is easy to adjust the clamping force according to the maximum pressure of the pressure limiting valve.

For a better understanding of the present invention, reference is now made to the preferred embodiment, represented in the drawings, which is described with the aid of specific terminology. Nevertheless,

ES 2 390 127 T3 it should be mentioned that it does not imply any limitation of the scope of protection of the invention, since this type of changes and other modifications of the device represented, as well as other applications of this type of the invention, such as those represented, must considered as current and future technical knowledge, usual, of an expert in the field. The figures show an example of embodiment of the invention, namely, figure 1 a perspective view of a column base, figure 2 a cross-sectional view of the column base along the line AA of figure 1, Figure 3 a perspective view of a foot-operated pump, connected with two locking cylinders, and Figure 4 a schematic representation of a hydraulic circuit.

In Figure 1 a column foot 10 for a table column of an operating table is shown in perspective view, and in Figure 2 the column foot 10 is represented in a section along the line AA of figure 1.

The column foot 10 comprises a bottom plate 12 located on the side of the floor (see FIG. 2) and a foot plate 14. The foot plate 14 continues vertically upwards in the form of a table column section 16. Other components of the table column, a column head of the table column and a supporting surface that can be attached to or is connected to the column head are not shown in the figures.

The foot plate 14 is housed rotatably about a vertical axis 18 in the bottom plate 12 located on the side of the floor. The support is formed by a ball track 20 which can be seen in the cross-sectional view of Figure 2.

To the bottom plate 12 located on the ground side, a circular ring 22 is bolted 23. The circular ring 22 has an inward-facing cantilever 24, which grips the foot plate 14 at its outer edge section 26 from above. The cantilever 24 of the circular ring 22 forms a counter support for the outer edge section 26 of the bottom plate 12, which prevents the foot plate 14 from lifting up from the bottom plate 12. Between the cantilever 24 of the circular ring 22 and the outer edge section 26 of the bottom plate 12 there is a vertical clearance, so that normally, that is to say when not locked in the manner described in detail below, the plate of foot 14 can be rotated about vertical axis 18 without being essentially braked by friction contact with cantilever 24.

On the foot plate 14 there is furthermore arranged a foot-operated pump 28, which in FIG. 3 is represented in a perspective view. As can be seen in Figures 1 and 3, the pump 28 has a foot lever 30, at the end of which a foot pedal 32 is arranged. rotate a pump shaft 34. As can be seen in Figures 1 to 3, a longer working cam 36 and a shorter unlocking cam 38 are arranged at one end of the pump shaft 34, the operation of which is described later.

The pump 28 is connected to two hydraulic locking cylinders 24, through hydraulic lines 40, arranged in the foot plate 14 (see Figures 1 and 2).

The pump 28 and the hydraulic locking cylinder 42 are connected via a hydraulic circuit which is schematically represented in FIG. 4 and which is described hereinafter together with the clamping function of the column foot 10.

In the unlocked state, the foot plate 14 can be rotated about the vertical axis 18 relative to the bottom plate 12, as mentioned above. In this way, a support surface (not shown) attached to a column head of the table column (not shown) can be rotated to a suitable position. Once the support surface has been rotated to a suitable position, the foot plate 14 is locked to the bottom plate 12 to retain the support surface from rotation about the vertical axis 18.

To lock or immobilize the foot plate 14, the foot pedal 32 of the foot lever 30 is depressed. In this way, through the working cam 36 the pump 28 is actuated and hydraulic oil is drawn from a tank of hydraulic oil 44 (see figure 4) through a suction valve 46. The hydraulic oil sucked in in this way is pumped, through a check valve 48 and the hydraulic line 40, to the hydraulic locking cylinder 42, whereby its pistons 43 extend (see figure 2) and bear on the bottom plate 12. As pressure builds in hydraulic conduit 40, foot plate 14 is lifted, thereby tensioning it with its outer edge sections 26 against cantilever 24 of circular ring 22. In this state, the foot plate 14 is locked in the circular ring 22 and can no longer be rotated about the vertical axis 18.

IS 2 390 127 T3

Check valve 48 causes conduit 40 to hold even after pumping is finished and thus foot plate 14 to remain locked to bottom plate 12 through circular ring 22.

As can be seen in figure 4, between the pump 28 and the check valve 48 there is arranged a discharge valve or pressure limiting valve 50. Said pressure reducing valve 50 is made in such a way that it opens towards the reservoir. of hydraulic oil 44 when the pressure between pump 28 and check valve 48 exceeds a predetermined maximum pressure. In this way, it is ensured that the pressure in the conduit 40 which is fed to the locking cylinders 42 never exceeds said predetermined maximum pressure.

By the construction described with the load reducing valve 50, the foot plate 14 locks onto the bottom plate 12 regardless of the mounting tolerances of the lock cylinders 42, always with a predetermined maximum clamping force corresponding to the maximum pressure of the pressure reducing valve 50. In particular, it is ensured that the clamping mechanism is not overloaded by too high a clamping pressure.

To release the clamp connection between the bottom plate 12 and the foot plate 14, the foot pedal 32 is lifted with the foot (see Figures 1 and 3). In this way, the unlocking cam 38 moves in a clockwise direction in the representation of FIG. 2, until it stops in an actuating section 52 (see FIG. 2) of an unlocking valve 54 that connects the hydraulic conduit 40 with the hydraulic oil reservoir 44 (see FIG. 4). When the unlocking cam 38 abuts the actuation section 52 of the unlocking valve 54, the latter opens, so that hydraulic oil escapes from the hydraulic conduit 40 to the hydraulic oil reservoir 44, reducing the pressure to which the valves are subjected. locking cylinders 42. In this way, the pistons 43 of the locking cylinders 42 are inserted, the foot plate 14 is lowered and the locking effect between the foot plate 14 and the bottom plate 12 is canceled.

In the illustrated embodiment of the column foot 10, a high locking effect can be generated with low handling forces. The locking mechanism is insensitive to manufacturing and assembly tolerances, since the system is not designed to achieve a predetermined lift stroke of the pistons 43 of the pressure cylinders 42, but rather to achieve a maximum contact pressure that it can be easily done with the help of the load reducing valve 50. Finally, the hydraulic locking system described here is characterized by a small construction space compared to the purely mechanical solutions customary up to now. The hydraulic oil can be guided with the conduit 42 through any path, so that the conduits 40 do not pose any obstacle for the other components, contrary to what is the case for example in a commonly used mechanical shaft. In particular, the construction space between the two locking cylinders 52 is kept free.

Although a preferred embodiment example is shown and described in detail in the drawings and in the foregoing description, this is to be considered as a mere example that does not limit the invention. It is noted that only one preferred embodiment is represented and described, current and future modifications made within the scope of protection of the claims are protected.