Linear electromechanical actuator for swing door

Abstract

Electromechanical actuator for swing door with a casing (2) comprising a lower half-shell (10) and an upper half-shell (16) that can be removably coupled together and delimiting an internal space housing an electric motor for driving a worm screw (6), to which is coupled, via a nut (24), the internal end of a tubular stem (20) coaxially housing said worm screw (6) inside it and having an internal end housed within said casing (2) and an external end articulated to said door (14), said stem being movable with respect to said casing (2) coaxially to said worm screw between a first extreme position, substantially contained within the casing itself and corresponding to the condition of the door (14) open, and a second extreme position, protruding from said casing (2) and corresponding to the condition of the door (14) closed, said casing (2) also being affected by a longitudinal slot (34) for guiding and positioning two limit stops (36,36') interfering with the axial movements of said stem (20) in correspondence with its two extreme internal and external positions, characterized in that each of said limit stops (36,36') is affected by a portion configured as a fork with its two prongs (44) extending towards said stem (20) beyond its longitudinal axis, so as to interfere with raised portions (25) protruding from the lateral surface of said stem (20) at least on opposite sides with respect to the axis of the latter.

Description

[0001] The present invention concerns a linear electromechanical actuator for swing doors.

[0002] Electromechanical actuators for swing doors are known, that is, for doors articulated in correspondence with a first substantially vertical axis to a fixed structure, for example to a metal or concrete pillar; they comprise an electric motor integral with the actuator, whose casing or body is articulated to the fixed structure in correspondence with a second substantially vertical axis, distinct from the first axis and is coupled, by means of a gear reducer and a substantially horizontal worm screw, to a nut coupled to a fork, in turn articulated to the door to be moved in correspondence with a third substantially vertical axis not coplanar with the previous ones.

[0003] More specifically, the actuator body comprises an elongated portion which houses the worm screw and is provided with a longitudinal slot for the passage of a support arm of a fork articulated to a blade which is in turn integral with the door to be moved.

[0004] The activation of the electric motor in both directions and the rotation of the worm screw driven by it causes the translation of the nut along the screw itself in both directions and the consequent rotation of the door when opening and closing.

[0005] Generally, the two end-of-travel positions of the door in opening and closing can be defined by two external stops, against which the door impacts in its two extreme positions; or, especially in the case of aesthetic, technical or regulatory constraints that do not allow the use of these external stops, by mechanical stops that are fixed to the body of the actuator in correspondence with the two positions of the nut along the worm screw in correspondence with the two extreme positions of the door and which can be adjusted in their position through the longitudinal slot obtained in the body of the actuator for the passage of the support arm of the fork connected to the door to be moved.

[0006] Regardless of the type of stops used, in these well-known electromechanical actuators the force generated by the electric motor to move the door develops along the axis of the worm screw, while the reaction opposed by the door to its movement passes through the point of articulation of the fork to the blade integral with the door itself and this can lead to the onset of moments which in particular situations, for example in the case of difficulty in moving the door, could lead to anomalous stresses on the actuator and on its attachments to the door and to the structure to which it is articulated .

[0007] Furthermore, the movement of the fork, to which the door is articulated, along the worm screw causes the free end of the actuator to approach the door during its movement, with a possible risk of interference if the connecting fork is not sized to keep the actuator sufficiently distant from the door, especially when the door is open. This requires the use of forks with particular configurations related to the specific installation to be carried out and in any case can increase the distance between the thrust axis, which coincides with the axis of the worm screw, and the reaction axis, which passes through the articulation between the fork and the door, and therefore can accentuate the previously indicated inconvenience.

[0008] Finally, the presence of the longitudinal slot for the passage of the fork connecting the actuator to the door to be moved, in addition to constituting a communication between the outside and the inside of the actuator body and therefore an inevitable passage of dust and humidity, can also constitute a danger for the user due to the lack of protection against the accidental introduction of a hand inside the actuator.

[0009] Also known are so-called "linear" electromechanical actuators, in which a tubular stem protrudes from the actuator body in line with the worm screw, which at the free end is provided with a fork articulated to a blade fixed to the door to be moved. In this type of actuator, the nut is directly fixed to the internal end of the tubular stem and the articulation between the actuator and the door is placed on the extension of the worm screw and therefore in line with it. In this type of actuator, the worm screw is not accessible from the outside and therefore there is no possibility of adjusting the mechanical stops along the actuator body from the outside so that they interact in the desired manner with the nut moving along the worm screw. Therefore, these well-known actuators do not have internal mechanical stops to limit the movements of the door and it is necessary to use electric limit switches, which however require a particular execution of the actuator, or external mechanical stops, i.e. fixed contrast elements, against which the door rests in the fully open condition and possibly also in the fully closed condition.

[0010] EP2638226 describes a linear electromechanical actuator equipped with a radial projection integral with the tubular stem of the actuator and configured to interfere with limit stops applied in an adjustable manner along a longitudinal slot made in the actuator body. This solution has partially solved the above-mentioned drawbacks but has nevertheless caused anomalous stresses on the actuator, on its attachments to the door and to the fixed structure and may be the cause of system malfunction. This is because the contrast between the radial projection and the limit stop elements integral with the actuator body develops along a line parallel to the axis of the latter but spaced from it and this nevertheless leads to the onset of moments that may cause anomalous stresses on the actuator.

[0011] Furthermore, the contrast between the radial projection integral with the tubular stem and the stop element integral with the actuator body requires a very precise reciprocal angular positioning and requires rigorous assembly precision and equally rigorous maintenance of their reciprocal positions, conditions which may be lost during use of the actuator due to deviations from these positions, due either to deformations resulting from such anomalous stresses or to play linked to the wear of the parts in reciprocal movement or to accidental impacts on the door by an external body, for example a vehicle.

[0012] The aim of the invention is to eliminate all these drawbacks and to create a linear electromechanical actuator for swing doors equipped with internal mechanical stops but in which all the abnormal stresses that generally arise when the tubular stem reaches the end-of-travel positions are practically eliminated.

[0013] In particular, the aim of the invention is to create a linear electromechanical actuator with internal mechanical stops that are easily accessible from the outside for their adjustment even by non-specialized personnel.

[0014] Another aim of the invention is to create a linear electromechanical actuator which, although equipped with a longitudinal slot for adjusting the internal mechanical stops, is free from all the drawbacks that such a longitudinal slot entails.

[0015] Another aim of the invention is to create a linear electromechanical actuator that can be applied to practically any type of door.

[0016] Another aim of the invention is to create a linear electromechanical actuator that is safe and reliable in operation.

[0017] All these aims and others that will result from the following description are achieved both jointly and separately, with a linear electromechanical actuator for swing doors as defined in claim 1.

[0018] The present invention is further clarified below in some of its preferred forms of practical embodiment reported for purely exemplifying and non-limiting purposes with reference to the attached tables of drawings, in which: Figure 1shows an exploded perspective view of a linear electromechanical actuator for a swing door according to the invention, Figure 2shows a perspective view of the enlarged detail enclosed by circle II in Fig. 1, Figure 3shows a perspective view of the enlarged detail enclosed by circle III in Fig. 1, Figure 4shows the actuator in lateral and partially sectioned view with the stem in the end-of-travel position completely retracted into the actuator body, Figure 5shows it in the same view as Fig. 4 but with the stem in the opposite end-of-travel position, Figure 6shows it in perspective view from below with the stem in the same position as in Fig. 4, Figure 7shows it in a schematic perspective view applied to a swing door in the closed condition, and Figure 8shows it in the same view as fig. 7 applied to the door in the open condition.

[0019] As can be seen from the figures, the linear electromechanical actuator according to the invention comprises a casing 2 or actuator body, which can advantageously house inside it a motor with a preferably vertical shaft, which inside the body 2 drives into rotation a worm screw (not shown) which couples with a helical toothed wheel 4, keyed to a worm screw 6. This worm screw 6 can advantageously be housed within a linear extension 8 of the body 2 which develops axially from a thicker part of the same, intended to house the electric motor.

[0020] For construction and maintenance reasons, the body 2 can be advantageously made in two separable half-shells , i.e. in a lower half-shell 10, to which the motor is applied and a fork 12 for articulated connection to the structure, to which the door 14 to be operated is articulated, and in an upper half-shell 16. The structure (not shown), to which the door 14 is articulated, can be made of a small pillar made of metal or concrete or masonry.

[0021] The two half-shells 10,16 of the body 2 18 can be advantageously held together by screws 18.

[0022] The extension 8 of the body 2 is affected at the free end by a circular opening, from which a hollow cylindrical stem 20 can emerge, which at the external end can advantageously have applied a fork 22 for the articulation of a vertical pin for connection to the door 14 to be moved, while at the internal end of the stem 20 an internally threaded nut 24 can be coaxially constrained, which is constantly engaged in the worm screw 6 running inside the hollow stem 20 and is advantageously affected by an annular relief 25 having an external diameter greater than the diameter of the stem 20, in order to protrude from the lateral surface of the latter.

[0023] The worm screw 6 can be supported in the vicinity of the helical gear wheel 4 by a rolling bearing 26 which is preferably retained by two semi-cylindrical guide cradles 28, obtained in the two half-shells 10,16.

[0024] The upper half-shell 16 can be associated, in correspondence with the circular opening of the extension 8 of the body 2, with an insert 30 affected by a semi-cylindrical cradle 32 and cooperating with a similar semi-cylindrical cradle 32' obtained in an insert 30', constrained to the lower half-shell 10, to delimit said circular opening and to support and guide the axial movements of the stem 20 with respect to the body 2, as will be seen better later.

[0025] The lower half-shell 10 can be advantageously affected by a longitudinal slot 34 of length preferably linked to the maximum axial excursion that the stem 20 can perform. This slot 34 is delimited by two edges 35 having internal and external bands preferably affected by a dense toothing configured to be engaged by elements 36,36' intended to constitute stops for the axial movements of the stem 20.

[0026] More specifically, each stop 36,36' can comprise a lower element 38, to be applied from the external side to the lower half -shell 10 in correspondence with the slot 34, and an upper element 40 to be applied always to the lower half-shell 10, but from the internal side, and to be secured to the lower element 38 preferably by means of screws 42 after having clamped together the two edges 35 delimiting the slot 34 of the lower half-shell 10.

[0027] The surfaces of the two elements 38,40 of each of the two stops 36,36' intended to come into contact with the toothed bands of the edges 35 of the slot 34, can be advantageously affected by toothed bands 41, cooperating with the toothed bands of said edges 35.

[0028] While the lower element 38 of each stop 36,36' is preferably flat, the corresponding upper element 40 is advantageously affected by a fork-shaped portion with two prongs 44 that extend towards the inside of the actuator body beyond the axis of the worm screw 6 and are configured to constitute a support for the annular relief 25 of the threaded nut 24 and therefore contrast the axial movements of the stem 20, to which said annular relief 25 is constrained. More particularly, the two prongs 44 constitute a support for the annular relief 25 in two points of the relief itself diametrically opposed to the axis of the relief itself which substantially coincides with the axis of the worm screw 6.

[0029] Preferably, the two prongs 44 of the stop 36' closest to the opening of the extension 8 of the actuator body for the passage of the tubular stem 20 are shaped in such a way as to delimit between them a passage and a guide for the stem itself, which in this way remains perfectly centered in its axial movements without requiring additional centering elements. For this reason, the distance between the two prongs 44 of this stop 36' must necessarily be no less than the diameter of the tubular stem 20 and constitute a support for the annular relief 25, which in practice could be replaced by a pair of radial reliefs developing horizontally from opposite sides of the tubular stem 20; at the same time the distance between the two prongs 44 of the other stop 36, i.e. the stop closest to the actuator motor, could be no greater than the diameter of the worm screw 6 and constitute the stop support for the threaded nut 24 and more generally for the assembly made up of the threaded nut 24 and the annular relief 25.

[0030] In an advantageous embodiment, the actuator according to the invention also comprises a strip 46 covering the slot 34 and the lower element 38 of the two stops 36,36'. More specifically, the strip 46, which can be made of metal or plastic material, is affected on the two longitudinal edges by teeth 48 for attachment to the lower half-shell 10, to which it can be advantageously fixed by snapping or with one or more screws 50, after the teeth 48 have been engaged in corresponding seats obtained in the lower half-shell itself.

[0031] The operation of the linear actuator according to the invention clearly follows from what has been described.

[0032] The operation of the electric motor of the actuator causes the rotation of the worm screw 6, which cannot perform axial movements but thanks to its coupling via the nut 24 with the stem 20 it makes the latter move axially and that is, depending on the direction of rotation of the motor, it makes it exit from the body 2 or re-enter it.

[0033] The ends of the axial travel of the stem 20 are defined by the two stops 36,36', which are adjustable in their position along the slot 34. To carry out this adjustment the screws 42 are loosened so that the two elements 38,40 of each stop can disengage their toothed portions 41 from the toothed bands of the edges 35 of the slot 34 and that the two stops can slide along it until they reach the desired positions, at which point they can be locked with a procedure in reverse to that which had unlocked them.

[0034] Thanks to the prongs 44 of the fork of the upper element 38 of both stops 36,36', when the annular relief 25 of the nut 24 rests on them, it prevents the further axial travel of the stem 20. This support can be made more effective and safe if the shape of said prongs 44 is complementary to the shape of the annular relief part 25 of the nut 24 which rests on them.

[0035] The position of the two stops 36,36' can be defined when the actuator is installed, that is, when the fork 22 of the external end of the stem 20 is constrained to the door 14 and the fork 12 is constrained to the structure, to which the door 14 is articulated.

[0036] Once the stops 36,36' have been correctly positioned, the strip 46 is applied to the lower half-shell 10, which completely covers the slot 34 and the visible part of the stops 36,36', as can be better observed in fig. 6 .

[0037] From what has been said it is clear that the linear actuator according to the invention is advantageous compared to traditional linear actuators and in particular: it is of the type with a tubular stem coaxial with the worm screw that drives the stem itself and is equipped with adjustable internal mechanical stops, allows you to adjust the stop position quickly and easily even with the actuator installed, it can be easily replaced with current traditional electromechanical actuators without requiring any adaptation work, eliminates any risk of accidental access to the internal parts of the actuator, completely hides the stops from view, while still allowing easy access to them for adjustments without requiring disassembly of the actuator, exerts a counteracting action on the axial movements of the stem exactly in line with such movements, eliminating any bending moment and any anomalous stress, which over time can alter the correct functioning of the actuator, ensures correct end-of-stroke stopping of the actuator stem regardless of its possible incorrect rotational positioning with respect to the actuator body, due either to installation inaccuracies or to movements linked to wear of the parts in reciprocal movement, or to deformations of the actuator articulation brackets due to accidental impacts by vehicles, it does not require any bracket to connect the nut coupled to the worm screw with the door and eliminates those precautions that must be adopted for the bracket of traditional actuators in order to avoid interference of the actuator with the door during its movement, exerts a thrust on the articulation point of the actuator on the door that is perfectly aligned with the axis of the actuator itself.

Claims

1. Electromechanical actuator for swing door with a casing (2) comprising a lower half-shell (10) and an upper half-shell (16) that can be removably coupled together and delimiting an internal space housing an electric motor for driving a worm screw (6), to which is coupled, via a nut (24), the internal end of a tubular stem (20) coaxially housing said worm screw (6) inside it and having an internal end housed within said casing (2) and an external end articulated to said door (14), said stem being movable with respect to said casing (2) coaxially to said worm screw between a first extreme position, substantially contained within the casing itself and corresponding to the condition of the door (14) open, and a second extreme position, protruding from said casing (2) and corresponding to the condition of the door (14) closed, said casing (2) also being affected by a longitudinal slot (34) for guiding and positioning two limit stops (36,36') interfering with the axial movements of said stem (20) in correspondence with its two extreme internal and external positions, characterized in that each of said limit stops (36,36') is affected by a portion configured as a fork with its two prongs (44) extending towards said stem (20) beyond its longitudinal axis, so as to interfere with raised portions (25) protruding from the lateral surface of said stem (20) at least on opposite sides with respect to the axis of the latter.

2. Actuator according to claim 1 characterized in that said raised portions are part of a single continuous circumferential relief (25).

3. Actuator according to claim 1 and / or 2 characterized in that each limit stop (36,36') comprises a pair of elements (38,40) to be applied externally and internally to said casing (2) and to be constrained together so as to engage the two edges of said slot (34) in a vice-like manner between said elements (38,40).

4. Actuator according to one or more of the preceding claims characterized in that at least one of the two edges of said slot (34) is affected by at least one toothed band (35) cooperating with a corresponding toothed band (41) obtained in each of said limit stops (36,36').

5. Actuator according to one or more of the preceding claims characterized in that the two elements (38,40) of each limit stop (36,36') are held together by screws (42) which can be operated from the outside of said casing (2) and loosened when said limit stops (36,36') must be made to slide along said slot (34).

6. Actuator according to one or more of the preceding claims characterized by the fact that it comprises a strip (46) covering said slot (34) and said limit stops (36,36').

7. Actuator according to claim 6 characterized in that said strip (46) is provided with teeth (48) for attachment to the lower half-shell (10) of said casing (2)8. Actuator according to claim 6 characterized in that said strip (46) is provided with at least one screw (50) for stable locking to said lower half-shell (10).

9. Actuator according to one or more of the preceding claims characterized in that said raised portions (25) belong to a continuous circumferential relief.

10. Actuator according to one or more of the preceding claims characterized in that said raised portions (25) of said stem (20) are integral with said nut (24).

11. Actuator according to one or more of the preceding claims characterized in that the distance between the prongs (44) of the limit stop (36') closest to the external end of said stem (20) is just greater than the external diameter of the stem itself, which is thus guided in its axial movements by said limit stop (36')12. Actuator according to one or more of the preceding claims characterized in that said circumferential relief (25) and the prongs (44) of each limit stop (36,36') have a complementary configuration for a shape coupling when they are in mutual contact.

Images