Electromechanical actuator for a hinged door panel

Abstract

 An electromechanical actuator for a door panel hinged to a fixed structure, characterised by comprising:
- an electric motor (6) with its casing rigidly fixable to said structure (4),
- a lead nut hinged to the door panel (2) to be moved,
- a lead screw (28) engaging said lead nut,
- a mechanical speed reduction coupling between the end of said lead screw (28) and the exit shaft of the motor (6), said mechanical coupling having a first degree of freedom about a substantially vertical axis and a second degree of freedom about a substantially horizontal axis perpendicular to the axis of said lead screw (28).

Description

[0001] The present invention relates to an electromechanical actuator for a hinged door panel.

[0002] Electromechanical actuators are known for hinged door panels of door gates, large doors and the like. They generally comprise an electric motor, a speed reduction unit associated with the electric motor, a lead screw fixed to the exit shaft of the speed reduction unit and a lead nut engaging said lead screw and hinged to the door panel. These components are housed in a casing to form the actuator, which at one end is hinged to a fixed structure about an axis parallel to the hinging axis of the door panel, and at its other end is hinged to the door panel.

[0003] During operation, the rotation of the electric motor varies the distance between the two axes about which the gear motor is hinged to the fixed structure and to the door panel, to cause the door panel to move in one direction or the other.

[0004] A drawback of these gear motors is that the electric motor is powered by a cable which starts from the fixed structure and which during movement of the door panel is subjected to periodical flexure, which tends to deteriorate it over time.

[0005] Another drawback is that with modern motors provided with encoders and/or electrical limit switches, in addition to electrical energy supply conductors further conductors also have to be provided for transmitting electrical signals, all this resulting in a cable of a certain diameter and hence of a certain rigidity, which magnifies the aforesaid drawback.

[0006] A further drawback is that the electric cable always represents a weak point of the system, as it is subjected to the action of branches, animals and children.

[0007] Another drawback is that as the motor is incorporated into the door panel operating arm, it has necessarily to satisfy certain limitations on its dimensions, these limitations resulting in limitations on the maximum power which the actuator is able to deliver. These power limitations, often combined with insufficient ventilation, result in limits on the usability of the actuator, especially in particular applications (businesses, apartment blocks, etc.) in which the door panels to be moved can be extremely heavy and the movements can be very frequent.

[0008] The drawback of motor size and cable dimensions is accentuated in the case of actuators with an incorporated control system, to the extent that many actuator manufacturers have renounced production of this type of product.

[0009] According to the invention all these drawbacks are eliminated by an electromechanical actuator for a door panel hinged as claimed in claim 1.

[0010] A preferred embodiment of the present invention is further clarified hereinafter with reference to the accompanying drawings, in which:

Figure 1 is a perspective view of an actuator of the invention installed between a pillar of an entrance door gate and the door panel hinged to it,

Figure 2 is a partially sectioned enlarged detailed perspective view of the mechanical coupling between the motor exit shaft and the lead screw which operates the lead nut.

[0011] As can be seen from the figures, the actuator of the invention is intended to move a door panel 2 hinged to a fixed structure consisting for example of a pillar 4. It comprises an electric motor 6 provided with an encoder and supported by the upper arm 8 of a C-shaped bracket 10 fixed by its vertically disposed central arm 12 to a vertical surface of the pillar 4 by screws 14. The vertical exit shaft of the motor 6 extends lowerly, within the space defined by the upper arm 8 and lower arm 8' of the bracket 10, as a vertically disposed lead screw 16 coupled to a helical ring gear 18. This ring gear 18 is keyed onto a horizontal shaft 20 supported via bearings 22 by the casing 24 of the arm 24 connected to the door panel 2. Specifically, this casing, which consists of two half-shells preferably made of die-cast aluminium or plastic material and connected together, is hinged about the axis of the shaft 20 to a cylindrical casing 26 housing the entire mechanical speed reduction coupling unit between the lead screw 16 and a horizontal lead screw 28 engaging in a threaded bush or lead nut (not shown in the drawings) which is hinged about a vertical axis to a bracket 30 fixed to the door panel 2.

[0012] This mechanical speed reduction coupling unit housed in the cylindrical casing 26 not only comprises the lead screw 16 and the helical gear 18 but also comprises a bevel gear 32 keyed onto the shaft 20 and engaging a bevel gear 34 of the same diameter keyed onto the lead screw 28.

[0013] The operation of the actuator of the invention is immediately apparent from the aforegoing description: rotating the motor 6 rotates the lead screw 16 which, by virtue of its engagement with the helical gear 18, causes the shaft 20 to rotate. This rotates the bevel gear 32 which, by virtue of its engagement with the gear 34, rotates the lead screw 28. The rotation of the lead screw 28 causes the lead nut to slide along it axially and which, being hinged to the door panel 2, causes this to move in one or other direction, depending on the direction of rotation of the electric motor 6.

[0014] From the aforegoing it is apparent that the actuator of the invention is particularly advantageous compared with traditional actuators, in that:

• installing the motor 6 directly on the pillar 4 eliminates floating cables and any movement thereof during operation of the door panel 2,
• the fixed motor 6 has non limit to its dimensions, and is completely hidden by the pillar 4 when viewed from the outside,
• the elimination of dimension limits on the motor 6 eliminates virtually any limit to its power,
• the elimination of dimension limits on the motor 6 and the elimination of floating cables means that motors can be provided with a control system and encoder or limit switch on board,
• the degree of freedom between the lead screw 16 and helical gear 18 about the axis of the lead screw 16 also constitutes the articulation between the door panel operating arm and the motor 6, and hence the pillar 4, making the actuator usable for both right handed and left handed applications,
• the degree of freedom between the two bevel gears 32, 34 about the axis of the shaft 20 also enable the door panel operating arm to move in a vertical plane and hence compensate any installation irregularities of the door panel 2 and/or motor 6 which lead to imperfect parallelism between the axis of the motor 6 and the hinging axis of the door panel 2,
• the operating arm for the door panel 2 has only to house the lead screw 28 and is therefore much slimmer than traditional actuators,
• the fixing of the actuator to the support structure no longer requires the use of a fork-type bracket, as in the past, hence the inevitable slack due thereto is completely eliminated.

Claims

1. An electromechanical actuator for a door panel hinged to a fixed structure, characterised by comprising:

- an electric motor (6) with its casing rigidly fixable to said structure (4),

- a lead nut hinged to the door panel (2) to be moved,

- a lead screw (28) engaging said lead nut,

- a mechanical speed reduction coupling between the end of said lead screw (28) and the exit shaft of the motor (6), said mechanical coupling having a first degree of freedom about a substantially vertical axis and a second degree of freedom about a substantially horizontal axis perpendicular to the axis of said lead screw (28).

2. An actuator as claimed in claim 1, characterised in that said lead screw (28) is housed in a casing.

3. An actuator as claimed in claim 1, characterised in that said mechanical coupling comprises a lead screw (16) rigid with the shaft of the motor (6) and a helical gear (18) keyed onto a substantially vertical shaft (20) on which a first bevel gear (32) is keyed, engaging a second bevel gear (34) keyed onto the lead screw (28) of the operating arm.

4. An actuator as claimed in claim 1, characterised in that the shaft (20) of said helical gear (18) is supported by support bearings (22) provided in a coupling casing (24, 26) housing the speed reduction unit (16, 18) and the bevel gear pair (32, 34).

5. An actuator as claimed in claims 2 and 4, characterised in that the casing (24) housing the lead screw (28) of the operating arm is hinged by a form fit to the casing (26) housing the speed reduction unit (16, 18) and the two bevel gears (32, 34).

6. An actuator as claimed in claims 1 and 4, characterised by comprising, for fixing the motor (6) to the fixed structure (4), a C-shaped bracket (10) with a central plate (12) for its fixing to said structure (4) and with two horizontal plates (8, 8') rigid with said central plate (12), the electric motor (6) being fixed upperly to the upper plate (8), and the casing (26) housing the mechanical speed reduction coupling unit being interposed between the two plates (8, 8').

7. An actuator as claimed in claim 3, characterised in that the two bevel gears (32, 34) have the same diameter.

8. An actuator as claimed in claim 1, characterised in that the motor (6) is provided with an encoder.

Drawing