Method and Actuating Device for Helical Switches

Abstract

The present invention relates to an actuating method and device which allows mechanically converting rotational movement into helicoidal movement, said helicoidal movement including considerable travel in the axial direction. To that end, the device comprises a rotating rod (1) inside a fixed outer body (2). The rod (1) comprises an emerging lug (4) sliding between two parallel surfaces (3) of the outer body (2), said parallel surfaces (3) being inclined with respect to the axial axis (5) of the rod (1).

Claims

1. Actuating device for mechanically converting rotational movement into helicoidal movement, characterized in that it comprises: a fixed body having a through cavity extending along an axis, said fixed body being provided with two guiding surfaces parallel to one another and arranged in an inclined manner with respect to said axis, and said guiding surfaces being arranged around said through cavity, a moving rod housed such that it has the capacity for movement in said through cavity, the moving rod being provided with a lug emerging radially with respect to an axial axis of the rod, where said lug is arranged tightly between said guiding surfaces, such that it can slide over them, making contact with both surfaces.

2. The actuating device according to claim 1, where the rotating rod comprises a first end emerging from one end of the fixed body, and a second end emerging from the other end of the fixed body, and where the second end is suitable for being coupled to the rotor of an electric switch.

3. The actuating device according to claim 1, where the lug has a width substantially coinciding with the gap between the two guiding surfaces.

4. The actuating device according to claim 3, where the lug has a spherical or semi-spherical portion.

5. The actuating device according to claim 1, where the through cavity is cylindrical and the rotating rod comprises two outer diametrically opposed surfaces, with a curvature coinciding with the curvature of the cavity.

6. The actuating device according to claim 1, where the guiding surfaces comprise an annular shape arranged around the through cavity, and where the guiding surfaces are accessible from outside the fixed body.

7. The actuating device according to claim 1, where the fixed body is formed by independent portions.

8. Method for mechanically converting rotational movement into helicoidal movement, characterized in that it comprises: rotating a rod in a guided manner inside a fixed body, said rod comprising a lug emerging radially with respect to an axial axis of the rod; sliding said lug over two parallel surfaces formed in the fixed body, said parallel surfaces being inclined with respect to the axial axis of the rod.

9. Electric switch comprising a stator and a rotor housed inside the stator, where the rotor can travel inside the stator, characterized in that it comprises an actuating device according to claim 1 coupled to the rotor to cause the helicoidal movement thereof.

Description

DESCRIPTION OF THE DRAWINGS

[0019] For the purpose of aiding to better understand the features of the invention according to a preferred practical embodiment thereof and to complement this description, the following illustrative and non-limiting drawings are attached as an integral part thereof:

[0020] FIG. 1 shows a perspective view of the actuating device according to a preferred embodiment of the invention.

[0021] FIG. 2 shows another exploded perspective view of the device of FIG. 1, where it can be seen that the device is formed by only four parts.

[0022] FIG. 3 shows several views of the device of the preceding figures in specific rod turning position, where FIGS. 3A and 3E are perspective views, FIGS. 3C and 3D are side elevational views, and FIG. 3B is a front elevational view. Parts of the outer body 2 have been omitted from FIG. 3E to help better see the rotating rod 1

[0023] FIGS. 4, 5 and 6 are views similar to those of FIG. 3 but in other rod turning positions.

[0024] FIG. 7 is a perspective view of the device of the invention in use, i.e., coupled to a helicoidal electric switch to cause helicoidal movement of the rotor of said switch.

PREFERRED EMBODIMENT OF THE INVENTION

[0025] FIG. 1 shows a perspective view of a preferred embodiment of the actuating device of the invention, whereby the steps of a preferred embodiment of the method of the invention are in turn implemented. The device comprises a rotating rod 1 introduced in a preferably cylindrical through cavity 10, i.e., it longitudinally goes through a fixed outer body 2, which is fixed in an external structure, for example an electric switch (not depicted) during device operation. The preferably metallic fixed body 2 in turn comprises two separate independent parts 2, 2′ defining between them a guide formed by two parallel surfaces 3, 3′, a lug 4 of the rod 1 being housed between said parallel surfaces 3, 3′. Said lug 4 is preferably semi-spherical and emerges radially with respect to the longitudinal axis 5 of the rod 1. The surface 3 is formed in part 2, and the other surface 3′ is formed in the other body 2′.

[0026] The lug 4 can consist of a metal sphere partially housed in a cavity of the rod 1, held by pressure.

[0027] The rod 1 comprises a first end 6 emerging from one end of the fixed body 2 for being coupled to a conventional external actuation mechanism (not depicted) to induce the initial rotational movement in the rod. At the end opposite of the fixed body 2, the rod 1 comprises a prolongation 7 with a through hole 8, said prolongation 7 being able to be coupled to a rotor having helicoidal movement inside the stator of a device to be actuated, usually an electric switch, as will be explained below in relation to FIG. 7.

[0028] FIG. 2 shows an exploded view of the same elements of FIG. 1 forming the actuating device. It can be seen that the rod 1 is a generally cylindrical body on which two parallel recesses 9 have been made for defining two outer diametrically opposed curved surfaces 12, 12′, with a curvature coinciding with the curvature of the through cavity 10, so that the rod can slide over the cavity, facilitating rotation thereof inside the fixed body 2. In other embodiments of the invention, the rod 1 can have any other section or any other number of recesses provided that it allows rotation thereof on the through cavity 10 of the fixed body 2.

[0029] In turn, the fixed body 2 is cylindrical for the most part, the central area thereof being interrupted by a planar and oblique cut that gives rise to the guiding surfaces 3 that are parallel to one another. That cut is a through cut, i.e., it transversely goes through the body 2, such that the guiding surfaces 3 are accessible from outside the fixed body 2.

[0030] Said planar cut is inclined with respect to the axial axis (X) of the cylinder, and the inclination and position thereof is halfway between the two ends of the body 2. It must again be noted that the fixed body 2 can have any other outer shape, provided that it allows housing the rotating rod 1 and has guiding surfaces 3 for guiding the lug 4. For example, the outer body can be integrated in a parallelepiped, or in any shape meeting the described requirements.

[0031] The inclination of the parallel surfaces 3 is adapted according to the axial travel to be obtained in the event of a specific angle of rotation. The greater the inclination with respect to the plane perpendicular to the axial axis (X), the more axial travel occurs.

[0032] The guiding surfaces 3 can be obtained by means of cutting a single part with the desired angle, giving rise to parts 2, 2′, or else by means of manufacturing the two parts 2, 2′ separately. In any case, manufacture of the actuating device is simple and can be readily adapted to considerable axial travel, without being subjected to the limitations of any type of machining equipment.

[0033] FIGS. 3 to 6 illustrate the working of the actuating device, showing four rotation positions thereof. FIG. 3 shows an initial position 0° in which the lug is in the position of the guide formed by the two guiding surfaces 3, 3′ farthest away from the prolongation 7. Therefore, said prolongation 7 emerges from the fixed body 2 a minimum distance D.sub.min.

[0034] In FIG. 4, the first end 6 of the rotating rod 1 is turned 90 degrees. Upon turning, the lug 4 moves forward along the guide until reaching an intermediate point of said guide. It must be noted that in the drawing, lug 4 is concealed by the rod 1 itself. The axial travel forced by the parallel surfaces 3 on the lug 4 forces the rod 1 to travel axially, the prolongation 7 emerging an intermediate distance D.sub.90. The particular value of said intermediate distance for a 90° turn can be chosen by simply changing the angle of inclination (α) of the guiding surfaces 3 with respect to the axis X.

[0035] In this preferred embodiment shown in the drawings, said angle of inclination (α) is close to 45°, but in other preferred embodiments it can be any angle ranging between 0° and 90°, excluding 0° and 90°.

[0036] In FIG. 5, the rod 1 rotates another 90° with respect to the position of FIG. 4 and in the same rotation direction, such that the lug 4 travels to the end of the guide farthest away from its initial position. As a result, the rod 1 reaches its greatest axial travel and the prolongation 7 emerges from the fixed body 2 a maximum distance D.sub.max.

[0037] Once the end of axial travel has been reached, if the rod 1 is still rotating in the same direction as shown in FIG. 6, the lug 4 continues rotating but the configuration of the fixed body 2, specifically the two guiding surfaces 3, 3′, forces it to move back in the axial direction. In the particular case of the drawing, for a 270° rotation the prolongation 7 moves back until emerging the same intermediate distance D.sub.90. Another 90 degree turn from said position would return the device to its initial position shown in FIG. 3.

[0038] In summary, the annular configuration of the guiding surfaces 3, 3′ and the arrangement thereof around the axis (X) coinciding with the axial axis 5 of the rod 1 adds longitudinal travel to the initial rotational movement, thereby obtaining helicoidal movement, said longitudinal travel furthermore being in a reversible direction, because it moves back and forth in the event of continued rotation in one and the same rotation direction.

[0039] Finally, FIG. 7 shows an electric switch 11 comprising a stator 12 and a rotor 13 housed inside the stator 12, where the rotor can travel inside the stator with respect to both rotation direction and longitudinal travel direction. The switch comprises an actuating device 1, 2 like the one described above, such that the rod 1 is coupled to the rotor 13 of the switch 11, and therefore said rotor 13 will perform said helicoidal movement inside the stator in order to connect and disconnect the contacts of the switch. The fixed body 2 is mounted in the stator 12 in a fixed manner.