The present invention relates to the industrial field of mechanizing door movements, in particular to a motor-driven mechanical device for moving door wings, especially those closing the cabin of an elevator. Review of the known art The devices for moving the wings of doors, such as those for closing elevator cabins, are at present realized by means of a belt or chain drive that, receiving movement from an ordinary fast motor, slows down its speed through a number of stages till it reaches a level compatible with movement of the wings of the door and with the safety of the user. Though delicate, these drive systems are heavy, noisy and bulky, requiring adequate adjustment and maintenance to keep them efficient.

An alternative is to use low-speed motors, obtained either by increasing the number of poles or by electronic regulation by means of an inverter. These motors and their systems are delicate, costly and complex where it becomes necessary to create a torque suitable for movement of heavy wings and where there is external friction.

A further alternative is offered by articulated leverages with sliding parts, but on account of their internal friction, these systems are to some extent inefficient, consume a large amount of energy, are noisy and wear out too quickly. Summary of the invention

Purpose of the present invention is to overcome the above drawbacks; its subject is therefore a device for working the wings of a door mounted at a passageway, comprising: an electrical motor with reduced number of revolutions, its shaft being mechanically coupled to a pintle of the wing, said pintle comprising a first element supporting the wing rigidly connected to a frame fixed to a wall that delimits the passageway on one side; there being in said first supporting element a first hole, in which a first pin fixed to the wing rotates, said pin being placed parallel to the shaft of the electric motor with reduced number of revolutions; a first crank one first end of which is rigidly connected to said first pin and a second end fixed to a second pin parallel to the first; - a first connecting element free to rotate around the second pin in proximity to a first end and having a second hole perpendicular to the second pin in proximity to a second end; a second crank rigidly connected to the drive shaft having one end fixed to a third pin parallel to said shaft; - a second connecting element free to rotate around the third pin situated in proximity to a first end and having a third hole perpendicular to the third pin placed in proximity to a second end; a first rod passing through the second and third hole; means to prevent the rod from sliding through the second hole and third hole, said means being fixed to the two ends of said rod in contact with the first and second connecting elements; controlling means designed to reverse the direction of rotation of the drive shaft and to hold the wing firm in the open position and in the closed position, as described in claim 1. From the functional standpoint, rotation of the drive shaft of the motor (at an angle less than 180°) causes rotation of the second crank (this being the main one), that pulls along one end of the rod by interposition of a pivoting element at the end of said crank. A similar element is situated at the other end of the rod to rotate the first crank (considered as secondary) in relation to the fixed frame, causing rotation of the pintle on the wing and of the wing itself. The fact of stopping the rod from sliding in the respective holes produces a constant distance between the pivoting elements during rotation of the main crank. Said rotation is therefore transferred, just as it is, to the second crank by the translating component of the movement made by the rod which in this way acts as a connecting rod. Further characteristics of the present invention considered innovative are described in the dependent claims.

According to one form of realization of the invention, symmetrical doubling of the above device enables a second wing to make a synchronized and symmetrical movement in relation to the first wing. In this way the bulk of each wing is about half the width of the opening and peripheral speed of each wing is halved, movement times being equal.

According to one aspect of the invention, the rods are inserted in a respective tubular element, pressed against one side of one of said connecting elements by a short spring coaxial with the rods; this compensates for any lack of precision that may appear when the device is being assembled.

According to an alternative form in which the invention can be realized, each wing comprises two identical panels hinged together, of which a first panel is hinged as stated, and, in a second panel, the side opposite the hinged side is fixed to two translating guides. In this way the bulk of each panel is equal to about one quarter of the width of the passageway. This solution can be repeated in the case of wings that have more than two panels.

The speed of movement of the wings and their thrust, exerted through the motor, are defined in accordance with the geometrical ratio between the length of the rod and the lengths of the main and secondary cranks connected to it. In any case the geometry of the device subject of the invention makes it possible to obtain dead times at the end of each stroke when either opening or closing the wings. These positions can be operated equally well by electrical control or by a mechanical stop. These means of control can be devised to regulate the speed of rotation and the torque of the motor, as well as to operate the movements, their times and pauses. The device is fitted with all the necessary safety systems to avoid damage to any obstacles that may impede movement of the wings. A battery system can also be used to run the device in the event of a failure of electricity. The device according to the invention preferably uses a combination of simple mechanical components in a design in which there are no sliding parts subject to wear, and which make it possible to work the wings by means of a return spring even if they are heavy and difficult to manoeuvre. In this way there are fewer parts and fewer different weights, less bulk, less noise, less wear and less maintenance. Although the device has been devised mainly for operating the wings of elevator cabin doors, its use covers a much wider range and is in no way limited by the particular shape of the wings of a door. When used in an elevator, the frame is fixed to the roof of the cabin, flush with the width of the passageway, to house the motor and supporting parts of the pins fixed into the wings. Still within the field of elevators, the means of control can bε designed to synchronise opening and closing of the cabin door with opening and closing of the door onto the landing. Short description of the figures Further purposes and advantages of the invention will be made clearer by the following detailed description and by the attached drawings provided for explanatory reasons only and in no way limiting, in which: - Figure 1 shows a perspective view of the upper part of the cabin of an elevator with application of the device for working the wings made according to the present invention. - Figures Ia and Ib show two details of the device in Figure 1.

Figure 2 gives a side view of a pivot pin of one wing of the device as seen in Figure 1. - Figure 3 shows a side view of a mechanical support in which the pin in

Figure 2 rotates.

Figure 4 shows a side view of a crank rigidly fixed to the pin in Figure

2. - Figure 5 shows a perspective view of a connecting block pivoted either on the crank in Figure 4 or on that in Figure 6.

Figure 6 shows a front view of another crank used in the device in

Figure 1.

Figure 7 shows the device in Figure 1 applied to an elevator cabin the wings of whose door are made using double panels set book- wise.

Figures 8, 9 and 10 show respective views from above of the device in

Figure 1 in an equivalent number of operative positions, respectively with the wings open, with the wings at 45° and with the wings fully closed. Detailed description of some preferred forms of realizing the invention

Figure 1 is a section view of the upper part of an elevator cabin 1 showing the roof, Ia, and two side walls Ib and Ic which, together with the floor and the rear wall, not visible in the figure, delimit a passageway for entry and exit from the cabin 1. Said passageway is opened and closed respectively by two wings 2 and 3. Flush with the passage and fixed to the roof Ia. is a frame 4 that houses a device for operating the wings 2 and 3. The frame 4 comprises a base 5, two sides 6 and 7 and a front wall 8 perpendicular to the base 5. Rigidly fixed to the side 6 are two mechanical supports 9 and 10, parallelepiped in shape, superimposed, the one spaced at a short distance from the other. In supports 9 and 10 is a hole through which passes a pin 11 fixed to the wing 2. Pin 1 1 emerges from the upper support 9 for a short distance fixed to a first end of a crank 12. The other end of the crank 12 supports a pin 13 parallel to pin 11. A connecting block 14, approximately parallelepiped in shape, pivots on the pin 13 of crank 12 at a first hole made at one end. In the other end of block 14 is a second hole, perpendicular to the first, from which emerges one end of a rod 15. Beyond the block 14, rod 15 passes through a tubular element 16 in contact with said block. The other end of rod 15 is fitted into a hole present at one end of a second connecting block 17, the same as block 14 described above, In the other end of block 17 is a hole into which is fitted a pin 18 parallel to pin 13. Pin 18 is raised up at one end of a crank 19 that supports a second pin 31 symmetrical to pin 18 in relation to the centre. Crank 19 is centrally fixed to the shaft 20 of a motor 21 producing reduced number of revolutions or to the shaft of a ratio-motor 21 mounted on the frame 4. Similar to the description of wing 2, two parallelepiped mechanical supports 22 and 23, superimposed and spaced at a short distance one from the other, are rigidly connected to side 7 of the frame 4. In supports 22 and 23 is a hole through which passes a pin 24 fixed to wing 3. Pin 24 emerges for a short distance from the upper support 22 fixed to one end of a crank 25. The other end of crank 25 supports a pin 26 parallel to pin 24. A connecting block 27, identical with the previous blocks 14 and 17, pivots on pin 26 at a first hole made in a first end. In the other end of block 27 is a second hole, perpendicular to the first, into which fits the end of a rod 28. Beyond the block 27, rod 28 passes through a tubular element 29 in contact with said block. The other end of rod 28 fits into a hole in one end of a further connecting block 30, identical with previous blocks 14, 17 and 27. In the other end of block 30 is a hole into which fits the pin 31 parallel to pin 26. The frame 4 houses an electronic deλ'icε 32 to control the direction of rotation of the drive shaft 20, and possibly angular velocity, as well as the open and closed positions of wings 2 and 3. Figure Ia shows in detail the connection between rod 28 and connecting block 30. Referring to the figure, it will be seen that the end of rod 28 emerging from block 30 is threaded and is screwed to one wall of said block by a nut 33 and by a second nut 34. Also visible is a helical spring 35 coaxial to rod 28 between block 30 and the tubular element 29. Figure Ib gives a detailed view of the connection between rod 28 and connecting block 27. Looking at the figure it will be seen that the end of rod 28, emerging from block 27, is threaded and screwed into a wall of said block by a nut 36. It will also be seen that the tubular element 29 is pressed against the opposite wall of block 27.

Figure 2 illustrates either pin H o pin 24. In the lower part of either pin 11 or 24 is a section 1 Ia of smaller diameter. A rectangular plate 1 Ib is fixed to the base of pin 11 at the point of transition between the two diameters. The free end of plate l ib is welded to a short cylindrical coupling 1 Ic the length of which is the same as that of the end section 1 Ia. Both elements 11a and 1 Ic are fitted into the thickness of the wing 2 (3). At the upper end of pin 11 is a part 1 Id for connection to the crank 12. Figure 3 shows one of the mechanical supports which may be any one of numbers 9, 10, 22 or 23. Referring to the mechanical support 9, the presence will be noted of a hole 9a in which is a bushing 9b for insertion of pin 11, and of two holes, 9b and 9c, placed crosswise to hole 9a for fixing the frame 4 to the side 6 (7). Figure 4 illustrates the crank, 12 or 25, consisting of two parallel sections, 12a and 12b, joined by a vertical section 12c, and rounded at the connecting points. The pin 13 (26) is welded to the free end of the longer section 12b of a trapezoidal shape (though not seen in the figure) widening out towards the free end. Referring to crank 12, the trapezoidal section 12b is fixed to the end Hd of pin 11.

Figure 5 illustrates one of the connecting blocks, either 14. 17, 27 or 30. Making arbitrary reference to block 14, it will be noted that its parallelepiped form tapers slightly at one end through which passes a hole 14a to receive the pin 13. At the opposite end is a hole 14b for insertion of one end of the rod 15.

Figure 6 shows a crank 19 consisting of a short bar rounded at its ends from which pins 18 and 31, welded to the bar, project upwards. Figure 7 shows a section view of the cabin 1 down to the floor Id. On looking at the figure it will be seen that double wings, articulated book- wise, are mounted at the two sides of the passageway. Wing 2 is here divided into two equal panels, 2a and 2b, joined by hinges 2c. Wing 3 is similarly divided into two equal panels, 3a and 3b, joined by hinges 3c. The free side of the two external panels, 2b and 3b, is fixed to two translation guides respectively flush with the floor and with the roof of the cabin 1. Operation of the device shown in the preceding figures is explained with the help of Figures 8, 9 and 10 wherein, compared with Figure 1, emphasis is given to a device for mechanically keeping wings 2 and 3 in the open and closed positions. This devices comprises two door stops, 39 and 40, mounted on a plate 37 fixed to the wall 8 of the frame 4, by means of spacers collectively numbered 38. The door stops 39, 40 are similar to two brackets that extend from the wall 8 towards the inside of drive shaft 20, separated from it by a distance less than half the length of crank 19. The door stops 39 and 40 each present a longitudinal groove, 41 and 42, in each of which is a short peg, respectively 43 and 44, parallel to the shaft 20. The pegs 43 and 44 project from their respective brackets for a length greater than the vertical distance between the brackets and the crank 19, and less than the vertical distance between the brackets and blocks 17 and 30; in other words they project for a length that intercepts the thickness of the crank 19 but does not exceed it.

Peg 43 lies at the end of the groove 41 nearest to the plate 37; peg 44 lies at the end of the groove 42 farthest from plate 37. Figure 8 shows the shape of the manoeuvring device for opening wings 2 and 3 of the cabin 1 to their fullest extent. In this illustration the main crank 19 is inclined at about 30° in relation to a horizontal axis passing through its centre. The secondary cranks 12 and 25 are trapezoidal in shape and the pins mounted at the two ends of both are misaligned. Rotation of the secondary cranks 12, 25 on pins 11 and 12 involves rotation of the respective wings 2, 3 due to the existing mechanical constraint. In the case of wing 2, pins 13 and 18 lie on opposite sides of rod 15 but, in the case of wing 3, pins 26 and 31 lie on the same side of rod 28. Rotation of crank 19 is stopped by the peg 44 (Figure 9) constrained by the door stop 40. The configuration given in Figure 8 is the same as that in Figure 1 if, when wings 2 and 3 are open, the crank 19 were inclined at an angle of a contrary sign. While the cabin is moving, wings 2 and 3 are locked and are only freed when the cabin 1 stops at a floor at which point the wings can be opened by hand or, preferably, automatically by a signal from the motor to a positioning sensor when the cabin 1 stops at a floor.

Figure 9 shows the position of the device when wings- 2 and 3 are open at 45°, this being obtained by an anti-clockwise rotation of about the same degree by crank 19, as indicated by the arrow. Compared with the preceding figure, a rotation can be seen by blocks 14 and 17 in relation to the cranks 12 and 19, and by blocks 27 and 30 in relation to cranks 25 and 19. Pegs 42 and 43 in the door stops 39 and 40 are not in contact with crank 19 which can therefore freely rotate.

Figure 10 shows the position of the device when wings 2 and 3 are fully closed, this being obtained by a further anti-clockwise rotation of about 45° by crank 19, as indicated by the arrow. Compared with the preceding figure, it will be seen that a further rotation of about 45° has been made by blocks 14 and 17 in relation to cranks 12 and 19, and of blocks 27 and 30 in relation to cranks 25 and 19. Rotation of crank 19 is stopped by peg 43 constrained by the door stop 39 .

Figures 8, 9, and 10 show that orientation of connecting blocks 14, 30, 17, 27 remains approximately unaltered. This means that they rotate at an angle such as to compensate rotation of the respective cranks to whose free ends these blocks are hinged. The combined effect of these rotating movements is to add an alternative translation component to rods 15 and 28, so that they act as connecting rods even though lacking a sliding block at one end. Based on the description given of a preferred example of the invention, a number of changes can obviously be made to it by an expert in the field without thereby departing from is sphere, as will be made clear by the following claims.