Locking joint for microscope support - has electromagnet acting on stack of spring washers to release or tighten friction grip to allow movement of coupling

(74) Agent: Rinuy, Santarelli,

14, av. of the Grande-Armée, 75017 Paris.

Certificate of previous addition (s):

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1.

This addition certificate relates to a device for block ing vertical axes in surgical microscope support installations, comprising several horizontal arms.

The main patent describes an arrangement for blocking telescopic tubular elements, intended more particularly for a suspension of a surgical microscope, using an electric current to generate a field for canceling the effects of several devices, with permanent magnet, of axial retention. vertical, the absence of current immediately causing this vertical axial retention.

A first certificate of addition attached to the main patent gives additional technical elements in the particular case where the suspension of the microscope is made up of horizontal elements articulated around vertical axes. The process of the main patent is applied in this first certificate of addition in relation to other retaining devices, but in rotary displacement.

This addition certificate describes other simpler and more operational means for blocking the vertical axes of the deployable horizontal elements of a surgical microscope support, this support being either a ceiling suspension or a support of the kind tripod resting on the ground.

In accordance with the present invention, the blocking of the various vertical axes is simultaneous in a single operation, said blocking being, as in the main patent, effective in the absence of electrical voltage and canceled in the presence of electrical voltage.

According to an advantageous embodiment of the invention, the locking device comprises a series of metal spring washers intended to frictionally block one or more discs integral with the axis to be blocked, an electromagnet with an intermediate lever being provided, moreover, for acting on said washers in order to cancel the friction of the washers on the discs, the blocking therefore being effective in the absence of an electric voltage applied to the electromagnet and canceled when an electric voltage is applied to said electromagnet.

2.

Other characteristics and advantages of the present invention will emerge from the description which follows, given with reference to the appended drawing in which:

- Figure 1 is an elevational view of a surgical microscope support with articulated horizontal elements, said support being a ceiling suspension;

- Figure 2 is an elevational view of another support with horizontal arms vertically articulated for surgical microscope, this support being of the tripod type resting on the ground;

- Figure 3 shows a blocking device according to the invention acting on a vertical axis of articulation of horizontal arms of a surgical microscope support installation.

In the embodiment shown, a vertical axis A of articulation between two horizontal arms, as shown in Figures 1 and 2, in the particular cases of a ceiling suspension and a support resting on the ground, is likely to be blocked by metal spring washers 1 acting on at least one disc 2 wedged on said axis A. More specifically, said washers act on a stop 3 integral with a rod 4 which passes through the washers and includes a clamping element 5 intended to clamp the disc 2 against a fixed console 6 itself traversed by the rod 4. The console 6 also carries an electromagnet 7, the rod 7A of which acts on a lever 8 articulated at 9 on the console 6. The articulated lever 8 is designed to act, in turn, on the rod 4.

In operation, in the absence of any electrical voltage applied to the electromagnet 7, the series of metal spring washers causes blocking by the clamping element 5 of the disc 2 secured to the axis to be blocked.

The energizing of the electromagnet 7 causes, by means of the lever 8, the crushing of the washers between the stop 3 of the rod 4 and the console 6 through which this rod passes. The crushing of the spring washers authorizes the disengagement of the disc carried by said rod 4.

3,

For a better tightening of the disc by the spring washers, the clamping element 5 can be balanced in its action by a shim 10 carried by the console opposite the disc 2 and of a thickness corresponding to the thickness of said disc 2.

In accordance with the invention, when the spring washers are actuated, no rotation, even very slight, of the axis A to be blocked is authorized. This is very important when the positioning of the microscope has been carried out, all the axes being in the unlocked state.

In the case, in particular of the tripod type support, it is essential that the horizontal arms are locked when said tripod is rolled or transferred on a cart from one room to another for example.

It is understood, finally, that the present invention has only been described and shown as a preferred example and that it will be possible to provide equivalences in its constituent elements without, however, departing from the scope of the invention which is defined in the claims which follow.

4.