The present invention relates to a linear actuator according to the preamble of claim 1.

Electrically driven linear actuators are widely used in structures, in which the linear movement is used for adjusting moveable parts. Be it moveable parts, which are rotatable around an axis or moveable parts, which are linearly displaceable . Thus, linear actuators are used in articles of furniture, hospital and care beds, patient lifters, in vehicles, boats and airplanes, machines and processing plants, satellite dishes, solar panels etc. The actuator is typically secured in a structure by means of a rear mounting on the rear end of the actuator and a front mounting on the activation element, which typically appears as a tubular rod.

Both the rear mounting as well as the front mounting is typically an eye or a fork mounting for a shaft, typically in the shape of a short shaft portion or a bolt. As an example of mountings, reference can be made to WO2005/079134 A2 to Linak A/S, wherein both the rear mounting as well as the front mounting is an eye. This is also the case in US 2,531,109 to Capmann, which discloses a linear actuator for landing wheels for airplanes. In US 2,465,601 to Ochtman the front mounting is likewise an eye, although designed as a separate element, which may be screwed into the end of the tubular activation element, such that it is possible to adjust the eye to the structure in which the actuator is incorporated. DE 20 2004 002 254 Ul to Dewert Antriebs- und Systemtechnik GmbH & Co. KG discloses a linear actuator wherein the rear mounting is a fork mounting, while the front mounting is an eye, which simply is designed as a hole in the free end of the tubular activation element. DE 299 19 214 Ul to Dewert Antriebs- und Systemtechnik GmbH & Co. KG discloses a linear actuator, wherein both the rear mounting as well as the front mounting is a fork mounting. A special embodiment of a linear actuator based on an U-profile is shown in DE 203 02 137 Ul to Dewert Antriebs- und Systemtechnik GmbH & Co. KG, but also in this case both the rear mounting as well as the front mounting is designed as an eye. Common to all the above structures is that the mountings allow for a movement of the actuator about one axis only. US 6,202,803 Bl to Lang discloses a linear actuator for adjusting slats (the front edges) and flaps on an airplane. Here, the rear mounting and the front mounting is designed with a spherical bearing, which is a troublesome and expensive construction, which does not always measure up to the desire for the linear actuator to be able to move about more than one axis. Furthermore, a rear mounting or a front mounting with a spherical bearing is rather voluminous and furthermore increases the built-in length of the actuator.

The purpose of the invention is to provide an electrically driven linear actuator with a mounting which enables the linear actuator to pivot around more than one axis without the use of a spherical bearing.

This is achieved according to the invention by designing the linear actuator as stated in claim 1 in that at least one mounting, by means of which the actuator can be secured in a structure in which the actuator is to be incorporated, comprises a first axis around which the actuator can pivot and where the first axis is located in an element in the mounting, said element can pivot around a second axis perpendicular to the first axis. Thus, the mounting can pivot around two axes, which in most cases solves the issue of the linear actuator not being able to pivot around more than one axis and further the solution is relatively simple and can thus be made relatively inexpensive, such that the solution can be widely used. Furthermore the construction can be made relatively small and short, i.e. the built-in length of the actuator is not increased or at least not considerably increased.

The element may of course be designed as a separate unit and be mounted in a recess in the rear mounting. In an embodiment the element is arranged in an insert located in a recess in the mounting. The element can thus be finished and positioned in the insert, which as a joint unit is placed in an insert in the mounting intended for that purpose. In an embodiment the element is designed as a cylindrical piece, where the first axis is perpendicular to the longitudinal axis of the cylindrical piece. The element can as a unit be cast as a cylindrical piece with a transverse opening or it can be made from a rod with a circular cross-section, ^" in which a transverse opening is created by means of drilling or in some other way. The insert can be a single element or can consist of more parts, depending on which construction is more fitting for the structure at hand. In an embodiment the insert is designed as two separate parts located diametrically opposite each other on the cylindrical piece. The manufacturing of the two parts is relatively simple and they can be identical and the mounting is likewise simple as it is only necessary to retain the parts around the element during the insertion into the recesses in the mounting. In an embodiment the two separate parts are designed as flat box-shaped elements, where the side towards the cylindrical piece is designed as a partially cylindrical surface, which fits the external side of the cylindrical piece. The recess in the rear mounting can thus be rectangular and in that the surfaces on the side of the rear mounting perpendicular to the first axis are plane the design will be simple while the mounting of the element will be easy.

It is understood that the mounting can either be a rear mounting or a front mounting depending on the specific structure in which the actuator is to be incorporated. It is understood that the linear . actuator further can be furnished with both a front mounting as well as a rear mounting of the present type.

For linear actuators which are particularly exposed to shocks, vibrations and unintended movements in the structure in which the actuator is incorporated, the front mounting or alternatively the rear mounting may be designed with an oblong opening for the first axis. Thus, it can somewhat be avoided that the linear actuator is exposed to unintended movements and vibrations in the structure .

Further characteristics of the invention will appear from the following embodiment of the invention, which will be described more fully below with reference to the accompanying drawing, in which:

Fig. 1 shows a perspective view of an actuator seen from the rear end,

fig. 2 shows a longitudinal section through the actuator,

fig. _. 3 shows a perspective view of a rear mounting seen from the rear end,

fig. 4 shows the rear mounting with a mounting bolt, fig. 5 shows an exploded view of the rear mounting, and

fig. 6 shows the rear mounting in fig. 5 pivoted around the vertical axis in the longitudinal axis of the rear mounting.

As it appears from figs. 1 and 2 of the drawing, the main components of the actuator are constituted by a housing 1, a reversible electric motor 2, a transmission appearing as a reduction gear 3, a spindle 4, a spindle nut 5, an activation element 6 in the shape of a tubular piston, also known as the inner tube, a guide 7 for this, also known as the outer tube and finally a rear mounting 8 and a front mounting 9.

In the embodiment shown the housing 1 is due to strength made from cast iron, such as aluminum and comprises a first cup-shaped part la and a second part lb, designed as an end cover, which is mounted on the end of the first part la by means of screws. The outer tube 7, which is an extruded tube of metal, such as aluminum, is with one end mounted in the first part la of the housing.

Through the reduction gear 3 the electric motor 2 drives the spindle 4, which with a bearing 10 on one end is embedded in the rear mounting. The spindle nut 5, located on the spindle 4, is secured against rotation and will thus move back and forth on the spindle depending on the direction of rotation of this. The tubular activation element 6 located in the guide 7 is with one end secured to the spindle nut 5 and thus follows the movement thereof, i.e. is displaced forward or retracted in the guide 7 depending on whether the spindle nut 5 moves back or forth on the spindle. As it appears from fig. 3 the rear mounting 8 is designed as a separate part of cast lightweight metal. The rear mounting comprises a first part 8a, by means of which it is mounted in the housing 1, to be exact in the second part lb of the housing namely the end cover, as well as a second part 8b, which protrudes through a hole in the second part lb of the housing intended for that purpose. A hexagonal collar 11 is located on the passage of the first part 8a to the second part 8b of the rear mounting, said collar can be received in a corresponding recess in the second part lb, the end cover, of the housing. The rear mounting can thus be adjusted in steps of 30° for adapting its position to the structure in which the actuator is incorporated. It is understood that other intervals of rotation can be applied, for instance the collar and the corresponding recess can be dodecagonal (twelve sided), such that the rear mounting can be adjusted in steps of 15°. The rear mounting 8 is retained by means of a nut 12, which is placed on the second part 8b of the rear mounting, protruding from the housing, and is screwed onto a threaded portion 13 against the outer side of the second part lb of the housing. Ring grooves 14 for a gasket are located between the hexagonal collar 11 and the threaded portion 13. A cylindrical part of the first part 8a of the rear mounting is equipped with a cylindrical recess functioning as a bed for the bearing 10 at the end of the spindle 3.

The second part 8b of the rear mounting, which protrudes from the housing 1, has a rectangular recess 15 with two opposite located end walls 15a, 15b and two opposite located side walls 15c, 15d. The recess 15 is intended for receiving an element 16 located in an insert 17. In the element 16 is an eye 18, in the shape of a through hole with a circular cross-section. The actuator can be mounted by means of a bolt 19 or a shaft portion through the eye 18 or in that the actuator with the eye 18 is positioned over a shaft or a pivot in the structure in which the actuator is to be incorporated. The actuator is thus capable of pivoting around the bolt, alternatively the shaft portion, the shaft or the shaft pin.

The element 16 is a "cylindrical piece", which with the end surfaces 19 is embedded on the side walls 15c, 15d of the recess 15. The element 16 consists of two halves 16a, 16b, where the walls facing each other, have a half- cylindrical hollow 18a, 18b and together form the eye 18. The external wall of the two halves 16a, 16b of the element is designed as a part of a cylindrical surface, where the two cylindrical surfaces together form the external cylindrical wall 20 of the element 16.

The element 16 is received in an insert 17, which fits into the rectangular recess 15 of the rear mounting 8. The insert is constituted by two separate parts 17a, 17b, where the two sides located diametrically opposite each other are shaped with a cylindrical surface 21 corresponding to the cylindrical wall 20 of the element 16 such that the element 16 can pivot around its longitudinal axis in the insert. The insert 17 with the element 16 is received as a unit in the rectangular recess 15 of the rear mounting in that the insert with the element fits between the end walls 15a, 15b in the recess .

As it e.g. appears from figs. 1 and 3 the rear mounting is designed with two opposite located plane surfaces 22,23, which eases the mounting of the rear mounting between two struts in a structure. Further, the two struts, when positioned closely up against the two plane side surfaces 22,23 on the rear mounting, will also effectively prevent the insert 17 and the element 16 from sliding sideward out of the recess 18 in the rear mounting 8.

The actuator can thus pivot about the bolt, alternatively the shaft portion, the shaft or the shaft pin and moreover, the actuator is able to pivot relative to the element where the bolt goes through the eye, i.e. the actuator is able to pivot around the longitudinal axis of the eye, just as it is capable of pivoting around an axis perpendicular to this, namely the axis of rotation of the element, cf. fig. 6 of the drawing. Furthermore, rotation around the longitudinal axis of the actuator is locked, as the activation element 6 is secured against rotation in the guide 7, which is advantageous.

As it appears from figs. 1 and 2 of the drawing the front mounting 9 is further designed as a separate component e.g. made from forged steel or cast lightweight metal. The front mounting comprises a first part 9a, namely a cylindrical part, by means of which the front mounting is secured in an outer end of the tubular activation element 6. A second part 9b of the front mounting has an opening 24 shaped as an oblong through hole. The actuator may with the front mounting 9 in a similar manner as the rear mounting 8 be mounted by means of a bolt or a shaft portion through the opening 24 or in that the actuator with the opening 24 is positioned over a shaft or a shaft pin in the structure in which the actuator is incorporated. The actuator is thus able to pivot around the bolt alternatively the shaft portion, the shaft or the shaft pin. Furthermore, the actuator is capable of displacing itself axially or the other way around, the structure in which the actuator is incorporated can move without affecting the actuator, in that the bolt or alternatively the shaft portion, the shaft or the shaft pin displaces itself in the oblong opening 24. The front mounting 9 can also be mounted or designed in such a manner that it will be able to pivot relative to the actuator. As it appears from fig. 2 the tubular activation element 6 is screwed onto the spindle nut 5. By leaving a number of threads free the activation element 6 with the front mounting 9 will be able to execute a rotary movement. The same will be possible in case the front mounting 9 is mounted with threads in the end of the tubular activation element 6. Alternatively, the front mounting 9 can be designed such that the two parts 9a, 9b of this can pivot relative to each other, i.e. the first part 9a is fixed in the end of the activation element, while the other part 9b with the opening 24 will be able to pivot relative thereto. It is understood that the front mounting just as the rear mounting 8 may be designed with an eye.