The invention relates to a drive operator for gates or doors.

The gates or doors are often moved by electric drive operators which have a wall-casing from which comes out a horizontally swivelling articulated arm, which transmits the motion from the drive operator to the gate or door.

Currently marketed are two different types of drive operators, characterized by different structures and mechanical components.

The most common type includes drive operators with a casing that contains the electric motor, the control electronics and the mechanical gearbox. The latter transmits the motion to the articulated arm through an appropriate output shaft, placed at the lower end of the operator, which moves the gate or door.

It is easy to guess that, though not essential, the electric motor, the mechanical gearbox and the articulated arm are turnable with respect to the same vertical axis.

The electric motor is of commercial type, the mechanical gearbox is made with known techniques and technologies, and the interconnection of the output shaft of the gearbox to the articulated arm is accomplished with special care and special materials, since it is subject to severe stress due to the movement imparted by the drive to the gate, or to stresses by the user directly on the gate, or to weather agents.

Other drive operators have a different manner of interconnecting the mechanical gearbox to the articulated arm. The electric motor and the mechanical gearbox are produced according to known methods, but the output shaft of the gearbox interacts with the toothing made inside the annular extremity of the articulated arm, placed in the lower region of the drive operator. This implies that the axis of rotation of the motor and the mechanical gearbox is different from the axis of rotation of the articulated arm.

This construction, especially for high power motors designed to move heavy industrial doors, is critical in performance. Since only a couple of teeth of a pinion meshes on the crown gear, on these teeth a considerable stress discharges. The pinion therefore must be made from resistant and thus expensive metal.

The stability of the articulated arm is affected too, because the external forces acting on the arm itself, e.g. an impact or wind on the gate door, must be countered eccentrically by the crown and the pinion as well as by the support means of the articulated arm. The condition of eccentricity of the pinion also imposes the use of centering and/or alignment and/or support means for the articulated arm on the casing, which complicate the structure.

An example of this type of construction is described in document U.S. 5 102 377.

In both types of drive operators, the increase of power in the electric motor and consequently in the weight of the gate call for a structural-technical adjustment of many mechanical parts, but particularly of the interconnection between the mechanical gearbox and the articulated arm. In both cases, the interconnection will use valuable and expensive materials. WO2008/053393 discloses a drive operator according to the preamble of claim 1. The main object of the invention is to improve the stability of the arm by lowering and balancing the internal stresses, particularly in the interconnection between the mechanical gearbox and the articulated arm.

A further object is to reduce production costs in spite of ensuring the necessary performance.

These objects are achieved by a drive operator as defined in claim 1, while preferred variants are defined in the dependent claims.

According to specific needs, a 2-, 3- or 4-geared epicyclical kinematic arrangement can be obtained. Keeping unchanged the size of the crown gear of the articulated arm and of the output shaft of the mechanical gearbox, in the space inside the crown gear there can be placed at least 4 equal gears. According to the needs, a minimum of 2 teeth in mesh (2 gears), at least 3 teeth in mesh (3 gears) or a minimum of 4 teeth in mesh (4 gears) are obtained.

The drive operator comprises an upper and a lower plate between which there is enclosed and mounted swivelly the arm, thus stability thereof is enhanced.

To facilitate the mounting of the satellite gears the lower plate comprises on the surface facing the articulated arm, pivoting means for the satellite gears, e.g. seats or holes or pins arranged like the vertices of an equilateral triangle and/or a square.

The advantages and features of the invention will be more apparent from the following description of an exemplary embodiment, with the attached drawing in which:

• Fig. 1 shows an exploded view of a drive operator according to the invention;
• Fig. 2 shows a second exploded view of the operator of Fig. 1 with some components assembled;
• Fig. 3 shows a three-dimensional view from below of the operator of Fig. 1;
• Fig. 4 shows schematically a variant of drive operator, which is not part of the invention.

With 10 is shown a drive operator according to the invention for a gate or door CG. It comprises a casing 12 which contains thereinto an electric motor and a gearbox assembly (72) (not shown). The gearbox assembly (72) is conneted to the first ouput shaft and comprises a second output shaft, to which a pinion (70) is connected. The pinion 70 goes through a plate 14 which forms the bottom of the casing 12, and transmits the motion to an internal toothing 36 provided on an end or hollow annular portion 34 of a swivel arm 30 having an actuation segment 32 articulated with a segment S connected to the gate CG. The arm 30 is swivelly mounted around the vertical axis X of the output shaft of the gearbox 72 between the plate 14, the upper one, and another, lower support plate 50. The two plates 14, 50 are clamped together in well-known manner at the time of assembly.

The annular end 34 rests on the plate 50 and contains in its lower part a circular crown or pedestal 52 facing the arm 30.

The pinion 70 is positioned at the center of the annular portion 34 and transmits rotary motion to the toothing 36 through the engagement of three equal satellite gears 60 which in turn mesh on the toothing 36. The gears 60 are mounted within the annular portion 34, arranged as the vertices of an equilateral triangle, and rotatably pivoted around a fixed axis through pins (not shown) anchored in holes 54 obtained on the circular crown 52.

Note that the holes 54 are seven, and arranged so that the axial pins and the gears 60 may be arranged in 3 different configurations. On a straight line and in opposite position (at 180 degrees), according to the vertices of an equilateral triangle (at 120 degrees) or by the vertices of a square (at 90 degrees), so that also four equal gears 60 can be used for different variants of increased stability and power. From the three configurations at least 2 meshing teeth (2 gears), at least 3 meshing teeth (3 gears) or a minimum of 4 meshing teeth (4 gears) are obtained.

It is apparent that when the pinion 70 rotates, it brings into rotation the gears 60 which in turn make the arm 30 rotate. Now the thrust on the toothing 36 is imparted by the contact teeth of all the gears 60, which also prevent decentralization thereof.

Note that the motor and/or the casing 12 may also lie under the swivel arm, essentially in a mirror structure to the one described.

Fig. 4 shows a, which is not part of the invention, of the invention, demonstrating how the position of the toothing on the swivel arm can be varied.

A swivel arm 132 has this time an annular portion 134 with an outer toothing 136. Two or more satellite gears 160 mesh with a toothing 161 thereof on the toothing 136. The gears 160 are driven through a toothing 163 thereof on a larger diameter by a central pinion 170 driven by the motor of the drive operator. The development circumferences of the toothings 161, 163 are coaxial and integral with each other.

The torque on the pinion 170 is discharged on the toothings 163, which in turn make the gears 161 rotate. These act on the toothing 136 rotating the arm 132.