WO2008035382A1

WO2008035382A1 - Actuating device for a door of a vehicle

Info

Publication number: WO2008035382A1
Application number: PCT/IT2006/000666
Authority: WO
Inventors: Gianni Turcatti; Massimo Sessa
Original assignee: Isaf Bus Components S.R.L.
Priority date: 2006-09-20
Filing date: 2006-09-20
Publication date: 2008-03-27
Also published as: DK2064407T3; EP2064407A1; EP2064407B1

Abstract

An actuating device (1) for a door (2) of a vehicle, particularly a bus, comprises: a support structure (5) comprising means (6) for connecting the device (1) to this vehicle, a door lifting unit (3) connected to the support structure (5) and which comprises a lifting member (4) movable between a lifted position and a lowered position and connectable to this door (2) such that this upward and downward movement results in a closing and opening movement of the door (2), blocking means (7) suitable to block this lifting member (4) in the lifted position, release means (8) suitable to release the blocking means (7) for allowing the lifting member (4) to be moved downward. This actuating device (1) comprises an auxiliary support device (9) distinct from the support structure (5) and removably connectable or connected thereto, wherein said blocking means (7) and said release means (8) are connected to this auxiliary support device (9).

Description

DESCRIPTION ^ACTUATING DEVICE FOR A DOOR OF A VEHICLE"

[0001] The object of the present invention is an actuating device for a door of a vehicle, particularly a bus, coach, or the like.

[0002] With particular reference to bus doors, the opening and closing movements thereof are usually provided by means of the combination of a translational movement and a rotary one. Particularly, when the door is being opened, it carries out a downward translation, such as to be disengaged from mechanical stops that are formed in the bus structure, and a rotation, such as to come outside the bus, thus clearing a passageway for the passengers . Similarly, the closure operation provides a rotation for repositioning the door at the passageway and an upward translation for engaging the door with the mechanical stops .

[0003] These movements are usually carried out by means of pneumatic actuating devices. [0004] The known pneumatic actuating devices comprise a lifting unit in the form of an electropneumatically- driven double acting cylinder. By moving in and out, the cylinder stem moves an upright connected to the door. [0005] Known actuating devices further comprise a support structure, which is usually shaped as an L-shaped support plate having a horizontal portion suitably drilled in order to allow the stem to slide therein, which is fixed to the cylinder head.

[0006] In several countries, such as in Italy, safety regulations provide that a door should be held closed also in the event of an accidental pressure loss occurring in the pneumatic supply system. To the purpose, known actuating devices comprise blocking systems that avoid the descent of the door upright on this occasion.

[0007] One of the most widespread solutions provides that, in the event of failure, the upright is constrained at the lower part thereof by a mechanical block, which prevents the same from moving down. [0008] The mechanical block usually consists of a roller supported by a lever that is directly hinged in the vertical portion of the L-shaped support plate and held by a spring in such a position that it abuts against a plate formed at the base of the upright. This roller is driven by a pneumatic cylinder, which is also directly fixed to the vertical portion of the L-shaped plate, which pushes it outside the periphery of the plate, when the upright is required to be moved down. To ensure that the door will open even in case a failure occurs in the pneumatic supply system, a leverage is provided, which is directly hinged to the L-shaped plate, and when manually operated, it acts on said roller for moving the latter outside the periphery of the plate, thereby allowing the upright to move down. [0009] These known actuating devices are not, however, without drawbacks.

[0010] As discussed above, the blocking system may be either provided or not, according to the country in which the bus operates. The presence of the blocking system entails a lot of processing being carried out on the L-shaped support, which processing is not required, on the other hand, when this system is not provided on the device. Consequently, the two types of devices have to be produced either independently from each other, or the two different productions are joined and the processing for providing the blocking system is also carried out in those devices which are not intended to be provided therewith. [0011] In the first case, doubling the production of the two different configurations mainly causes a considerable increase in the overall production cost. Furthermore, converting the device from one configuration to another is very laborious, because this requires complicated assembly and disassembly operations, as well as possible additional processing. [0012] In the second case, the design and production of a device not being provided with a blocking system result to be considerably bound to the characteristics of the device being provided with this system, since the weakening of the material due to the unnecessary processing on the L-shaped support requires to be compensated with a larger size. Furthermore, this unnecessary processing entails further production costs. [0013] The object of the present invention is thus to provide an actuating device for a door of a vehicle that overcomes the drawbacks cited with reference to the prior art.

[0014] Particularly, the object of the present invention is to provide an actuating device equipped with the blocking system, which can be easily converted to the configuration not provided with a blocking system, and vice versa.

[0015] A further object of the present invention is to provide an actuating device having such characteristics that the processing required in the configuration provided with a blocking system do not influence the design and production of the device in the configuration not provided with such a system. [0016] These and other objects are achieved by means of an actuating device for a door of a vehicle, particularly a bus, which comprises:

[0017] - a support structure, comprising means for connecting the device to said vehicle;

[0018] - a door-lifting unit connected to the support structure and comprising a lifting member movable between a lifted position and a lowered position, and that can be connected to said door, such that the upward and downward movement results in a closing and opening movement of the door;

[0019] - blocking means suitable to block this lifting member in the lifted position;

[0020] - release means suitable to release the blocking means in order to allow the downward movement of the lifting member,

[0021] wherein the actuating device comprises:

[0022] - ^■ an auxiliary support device distinct from the support structure and removably connectable or connected thereto, wherein said blocking means and said release means are connected to the auxiliary support device.

[0023] These objects are further achieved by means of an auxiliary support device, which is distinct from and removably connectable to an actuating device for a door of a vehicle, particularly a bus, this actuating device comprising:

[0024] - a support structure, comprising means for connecting the actuating device to said vehicle;

[0025] - a door-lifting unit connected to the support structure and comprising a lifting member movable between a lifted position and a lowered position, and that can be connected to said door, such that the upward and downward movement results in a closing and opening movement of the door;

[0026] wherein blocking means suitable to block this lifting member in the lifted position and release means suitable to release the blocking means to allow the lifting member to move down are connected to this auxiliary support device. [0027] In order to better understand the invention and appreciate the advantages thereof, some exemplary and non-limiting embodiments of the same will be described herein below, with reference to the annexed drawings, in which:

[0028] - Fig. 1 is a perspective view of an actuating device according to the invention;

[0029] - Fig. 2 is a perspective view of the actuating device in Fig. 1 from a different point of view; [0030] - Fig. 3 is a side view of an actuating device according to a further embodiment of the invention;

[0031] - Fig. 4 is a side view of an auxiliary support device according to the invention;

[0032] - Fig. 5 is a side view of the auxiliary support device opposite to that in Fig. 4;

[0033] - Fig. 6 is a perspective view of an actuating device according to a further embodiment of the invention;

[0034] - Fig. 7 is a side view of an actuating device according to the invention in a particular condition of use;

[0035] - Fig. 8 is a perspective view of the actuating device in Fig. 7.

[0036] With reference to the figures, an actuating device for a door 2 of a vehicle, particularly a bus, coach or the like is designated with numeral 1.

[0037] The actuating device 1 comprises a lifting unit 3 for the door 2, which comprises a lifting member 4 displaceable between a lifted position, corresponding to a closed position of the door 2, and a lowered position, corresponding to an open position of the door 2.

[0038] The actuating device 1 further comprises a support structure 5 connected to the lifting unit 3 , which comprises means 6 for connecting the actuating device 1 to the vehicle for which this device is intended.

[0039] In order to ensure that the lifting member 4 is held in the lifted position, and thus the door 2 is held closed, even in case of failure, the actuating device 1 comprises means 7 for blocking this lifting member 4.

[0040] In order to allow the lifting member 4 to move downward, and thus the door 2 to open, the actuating device 1 comprises release means 8 that are suitable to release the blocking means 7.

[0041] The actuating device 1 comprises an auxiliary support device 9, which is distinct from the support structure 5 and can be connected/disconnected thereto/therefrom in a removable manner. Advantageously, the blocking means 7 and release means 8 are connected to this auxiliary support device 9. Thereby, the actuating device 1 can be easily converted to the configuration not provided with a blocking device, and vice versa, by simply disconnecting and reconnecting the auxiliary support device 9 to the actuating device 1. Furthermore, the processing required for assembling the blocking means 7 and release means 8 to the actuating device 1 involve only the auxiliary support device 9, and not the support structure 5.

[0042] The actuating device 1 is preferably pneumatically actuated, and to the purpose the lifting unit 3 comprises a pneumatic, double acting main cylinder- piston unit 10 that comprises a stem 11, which by being operated by the piston of the main cylinder-piston unit 10 (not shown in the figures) , carries out the upward and downward movements required for closing and opening the door 2.

[0043] Advantageously, a hollow upright 12 connected to the door 2 of the vehicle is applied to the stem 11. The stem 11 and the upright 12 are coupled to each other such that the translations of the stem 11 can result in translations and rotations of the upright 12 and the door 2. Preferably, this coupling is of the screw- nutscrew type, particularly the stem 11 comprises an outer thread 13 suitable to be engaged with a corresponding thread formed in the inner cavity of the upright 12 (not shown in the figures) .

[0044] Herein below, the side of the device facing the upright 12 will be designated as the "upper" side, and the side opposite the upper side will be designated as the "lower" side.

[0045] Advantageously, the support structure 5 comprises a substantially L-shaped plate 14, which is connected to the main cylinder-piston unit 10, such that the upper portion of this main cylinder-piston unit 10 faces the lower face of the horizontal portion of the L of the L- shaped plate 14. Preferably, the coupling is carried out by means of threaded connecting members, particularly screws that are screwed in threaded holes (not shown in the figures) formed in the upper portion of the main cylinder-piston unit 10.

[0046] The L-shaped plate 14 comprises a through hole that is positioned such as to allow the stem 11 to slide, when the actuating device 1 is assembled.

[0047] Advantageously, the vertical portion of the L- shaped plate 14 comprises a plurality of through holes 15 for screws to pass therethrough, which are to be screwed in corresponding threaded seats (not shown in the figures) of the vehicle structure, such as to provide the connection of the actuating device 1 to this vehicle .

[0048] According to further embodiments, the L-shaped plate 14 comprises one or more seats suitable to house and fix further components for operating the actuating device 1, such as pneumatic valves, electric switches, electric connectors, or mechanical guides. [0049] Advantageously, the auxiliary support device 9 comprises a substantially plane auxiliary support plate 16, which can be removably connected to the L-shaped plate 14.

[0050] To the purpose, the actuating device 1 comprises means for removably connecting the auxiliary support plate 16 to the L-shaped plate 14. Preferably, these removable connecting means comprise threaded connecting members, particularly one or more threaded seats being formed in one of the side edges of the horizontal portion of the L-shaped plate 14. Still more preferably, these threaded seats are two and are formed on one of the two side edges of the L-shaped plate 14 adjacent to the vertical portion thereof, such that the total depth dimensions are reduced when the actuating device 1 is assembled and connected to the vehicle structure. The connection of the auxiliary support plate 16 to the L- shaped support plate is advantageously carried out by screwing screws 17 in said threaded seats of the L- shaped plate 14. To the purpose, the auxiliary support plate 16 comprises through holes 41 corresponding to the threaded seats of the L-shaped plate 14 and transversally shaped such as to ensure the abutment by the heads of the screws 17. [0051] Herein below, the side of the auxiliary support plate 16 facing the L-shaped plate 14 when the connection has been carried out will be designated as the "inner" side (Fig. 4) , and the side opposite the inner side will be designated as the "outer" side (Fig. 5) .

[0052] Furthermore, in order to define the "clockwise" and "counter-clockwise" directions of rotation, the inner side of the auxiliary support plate 16 (Fig. 4) will be taken as a reference.

[0053] Advantageously, to the auxiliary support plate 16 there are connected the blocking means 7 and release means 8, such that the latter can be also removably connected to the L-shaped plate 14 by means of the simple connection of only the auxiliary support plate 16.

[0054] In accordance with an embodiment, the blocking means 7 connected to the auxiliary support plate 16 comprise a first cam 18 and a second cam 19 that are pivotally connected to an upper portion of the inner side of the auxiliary support plate 16.

[0055] Advantageously, the first cam 18 is elastically loaded in a blocking position, e.g. by a helical spring 20, which is fixed such as to release its elastic energy between the first cam 18 and the auxiliary support plate 16.

[0056] Further advantageously, the first cam 18 has a profile that is shaped such as to form a support projection 21 and a recessing seat 22. The support projection 21 functions as a stop abutment for a plate 23 being formed at the base of the upright 12 when the latter is in the lifted position (door closed) . The recessing seat 22 is suitable to be engaged with a lock portion 24 formed by the profile of the second cam 19. Thereby, when the lock portion 24 of the second cam 19. engages^' the recessing seat 22 of the first cam 18, the latter can bear the weight of the door 2 and upright 12 transmitted thereto by means of the plate 23, because it is supported by the second cam 19. When this engagement is removed by rotating the second cam 19 in the counterclockwise direction in a release position, the first cam 18 is no longer capable of bearing the weight transmitted by the plate 23 and thus rotates in the counter-clockwise direction by being pushed by the plate 23 of the upright 12 against the elastic force of the spring • 20 (door opened) . When the upright 12 is lifted again, the spring 20 causes the first cam 18 to rotate clockwise thus taking back the latter to an angular position suitable to allow the engagement of the recessing seat 22 of the first cam 18 by the lock portion 24 of the second cam 19.

[0057] Advantageously, the release means 8 are connected to the second cam 19, such as to govern the movements thereof .

[0058] These release means 8 advantageously comprise first release means, preferably pneumatically operable, which ensure the regular downward movement of the upright 12 under regular conditions of use, i.e. in the absence of failures in the pneumatic supply circuit (not shown in the figures) .

[0059] Further advantageously, the release means 8 further comprise second release means, preferably mechanically operable, which ensure the downward movement of the upright 12 and consequently the opening of the door 2 also in the presence of failures in the pneumatic supply circuit and pressure loss.

[0060] The first release means advantageously comprise a pneumatic and a single-acting release cylinder-piston unit 25 that is in fluid communication with the main cylinder-piston unit 10. The release cylinder-piston unit 25 is preferably laterally fixed to the auxiliary support plate 19, e.g. by means of welding. The release cylinder-piston unit 25 is positioned such that an outer end of a stem 26 thereof can be connected to the second cam 19. Thereby, by moving out and in, the stem 26 causes rotations of the second cam 19, clockwise and counter-clockwise, respectively. Furthermore, the single-acting release cylinder-piston unit 25 is positioned and configured such that, in the absence of pneumatic- supply, due to the elastic bias of a spring inside the cylinder body (not shown in the drawings) , the stem 26 is held in a position suitable for holding the second cam 19 in the blocking position. In the presence of a pneumatic supply from the main cylinder- piston unit 10, the stem 26 moves at least partially into the release cylinder-piston unit 25 and causes the second cam 19 to rotate counter-clockwise, such as to take the first and second cams 18 and 19 to the release position (door opened) .

[0061] In accordance with an embodiment, the stem 26 is externally threaded at the end thereof outside the release cylinder-piston unit 25. Thereby, stops 42 can be provided on the stem 26, such as nuts and eventually washers that are arranged such as to form unilateral constraints both above and below a moving portion 43 formed by the profile of the second cam 19 (Fig. 3) . Thereby, the translations of the stem 26 can be converted into rotations of the second cam 19. [0062] The second release means advantageously comprise cable means connected to the second cam 19 as well as with a lever 27 that interacts with an emergency valve 33 for "the main cylinder-piston unit 10 such that, in response to an actuation of the cable means, the emergency valve 33 empties the main cylinder-piston unit 10 and the second cam 19 releases the first cam 18 and thus the upright 12.

[0063] These cable means advantageously comprise a cable 30 that passes through the release cylinder-piston unit 25 in a substantially coaxial manner.

[0064] This cable 30 is fastened at the end of the stem 26 by means of a first stop 31 and at the end 28 of the lever 27 by a second stop 32, such as to be held tensioned. Thereby, a kinematic chain is provided such that, when the lever 27 is rotated counter-clockwise, the stem 26, which is pushed by the cable 30 operated by the lever 27, moves downward and consequently the second cam 19 rotates counter-clockwise thus releasing the first cam 18 (release position) . This mechanism is advantageous when pressure is absent in the pneumatic circuit and the release cylinder-piston unit 25 has to be operated in a manual, rather than pneumatic, manner for allowing an emergency opening of the door 2. [0065] Advantageously, the lever 27 comprises a projecting portion 35 that is positioned and oriented such that, when the lever 27 is operated, i.e. rotated counterclockwise, to allow for the emergency opening, the projecting portion 35 presses a push-button 34 of the emergency valve 33, thus activating the latter and consequently emptying the main cylinder-piston unit 10 from the residual air provided within the lower chamber thereof, and allowing the upright 12 to be completely moved downward.

[0066] In accordance with an embodiment, the second release means comprise one or more emergency handles 36 (Fig. 3, 7, 8), preferably one to be positioned outside and one to be positioned inside the vehicle. These emergency handles 36 are connected to the lever 27, preferably by means of as many emergency cables 37 passing through a drilled plate 38 fixed to an upper edge of the vertical portion of the L-shaped plate 14. Thereby, when the emergency handle 36 is acted upon, the lever 27 will be operated thus taking the second cam 19 in the release position due to the kinematic chain provided by the cable 30.

[0067] In accordance with an embodiment, the blocking means 7 further comprise selective blocking means suitable to prevent the door 2 from being opened in manual manner by means of the emergency handles 36 when the vehicle speed is higher than a minimum speed (Fig. 6) . These selective blocking means advantageously comprise a pneumatic single-acting safety cylinder 39, with a stem 40 that, in the presence of pneumatic power supply, is engaged within a seat (not shown in the figures) of the second cam 19 being provided at the moving portion 43 thereof. This engagement prevents the second cam 19 from rotating counter-clockwise, such that the cam 19 does not move to the release position when one of the emergency handles 36 is acted upon.

[0068] Under a minimum speed of the vehicle, the pressurized air supply to the safety cylinder 39 is closed and the stem 40 thereof is elastically retracted thus releasing the second cam 19. Since the safety cylinder 39 is single-acting, the stem 40 is retracted even in case of accidental failure of the pneumatic supply circuit, thus allowing for the emergency opening of the door 2.

[0069] A description of the operation of the actuating device 1 according to the invention under several conditions of use will be provided herein below.

[0070] Under door-closed conditions and in the absence of failure to the pneumatic supply system, the lower chamber of the main cylinder-piston unit 10 is filled of pressurized air, such that the stem 11 thereof and the upright 12 are in the lifted position. The release cylinder-piston unit 25 is maintained emptied, such that the lifting member and thus the stem 26 thereof are fully lifted and that the first and second cams 18 and 19 are mutually engaged in the blocking position (door closed) . In the event of a failure in the pneumatic power supply system, the fall of the upright 12 caused by the pressure loss within the lower chamber of the main cylinder-piston unit 10 is prevented by the support projection 21 of the first cam 18, which abuts against the plate 23 of the upright 12.

[0071] When, under normal operating conditions, the door 2 has to.be opened, pressurized air is blown to the upper chamber of the main cylinder-piston unit 10 and therefrom to the release cylinder-piston unit 25. Thereby, the stem 26 of the release cylinder-piston unit 25 moves in and causes the second cam 19 to rotate counter-clockwise, thus releasing the first cam 18 that it thus free to rotate counter-clockwise. The upright 12, that is pushed by the weight force and by the pressurized air in the upper chamber of the main cylinder-piston unit 10, can thus move downward without finding the constraint provided by the first cam 18, thus allowing the door to be opened.

[0072] In order to close the door 2 under normal conditions, pressurized air is provided to be blown to the lower chamber of the main cylinder-piston unit 10, such that the upright 12 moves upward. The first cam 18, which is free of the forces transmitted by the plate 23, rotates clockwise due to the elastic action of the spring 20. The second cam 19 rotates clockwise due to the elastic outward movement of the stem 26 of the safety cylinder 25, not powered, until the lock portion

24 of the second cam 19 engages the corresponding recessing seat 22 of the first cam 18, thus ensuring that the downward movement of the upright 12 is blocked. [0073] In the event of a failure in the pneumatic supply system, the door 2 is opened by acting on one of the emergency handles 36, which tensions the emergency cable 37, which causes the lever 27 to rotate counterclockwise. The lever 27, by acting on the cable 30, causes the stem 26 of the release cylinder-piston unit

25 to move inside. Thereby, the second cam 19 rotates counter-clockwise thus releasing the cam 18. The projecting portion 35 of the lever 27 acts on the pushbutton 34 of the emergency valve 33, that sets the main cylinder-piston unit 10 to discharge. Thereby, the upright 12, which is subjected only to the weight force, is free to move downward, thus allowing for the emergency opening of the door 2.

[0074] From the description provided above, those skilled in the art may appreciate how the actuating device for a door of a vehicle according to the invention resolves the problems connected to the actuating devices according to the prior art . [0075] Particularly, those skilled in the art will appreciate how the actuating device according to the invention can be converted, by means of simple operations, to the configuration not provided with a blocking system, and vice versa, by simply removing and reconnecting the auxiliary support plate to which the blocking and release means are connected.

[0076] Those skilled in the art will further appreciate how the auxiliary support plate is the only portion of the actuating device which requires to be processed in view of the assembly of the blocking means and release means. The L-shaped support plate to which the auxiliary support plate is applied requires only processing suitable to allow this connection and not processing aimed at mounting the blocking and release means (cams, rollers, levers, cylinders, valves) . Consequently, the design and manufacture of the actuating device in the two versions can be unified, since the auxiliary support plate is the only component subjected to extra processing, which is constructively independent from the remainder of the actuating device.

[0077] To the embodiments described above, those skilled in the art, aiming at satisfying contingent and specific requirements, may carry out a number of modifications, adaptations and replacements of elements with functionally equivalent ones, without however departing from the scope of the claims below.

Claims

1. An actuating device (1) for a door (2) of a vehicle, particularly a bus, comprising:

- a support structure (5) , comprising means (6) for connecting the device (1) to said vehicle; a door-lifting unit (3) connected to the support structure (5) and comprising a lifting member (4) movable between a lifted position and a lowered position, and that can be connected to said door (2) , such that said upward and downward movement results in a closing and opening movement of the door (2) ;

- blocking means (7) suitable to block said lifting member (4) in the lifted position;

- release means (8) suitable to release the blocking means (7) to allow the downward movement of the lifting member (4) , characterized in that it comprises:

- an auxiliary support device (9) distinct from said support structure (5) and removably connectable or connected thereto, wherein said blocking means (7) and said release means (8) are connected to said auxiliary support device (9) .

2. The actuating device (1) according to claim 1, wherein said auxiliary support device (9) comprises a substantially plane auxiliary support plate (16) .

3. The actuating device (1) according to claim 1 or 2, wherein said blocking means (7) comprise a first cam

(18) movable between a blocking position in which it engages the lifting member (4) in order to block the latter in the lifted position and a release position in which it releases the lifting member (4) , and a second cam (19) movable between a blocking position, in which it engages the first cam (18) in order to lock the latter in the blocking position thereof, and a release position, in which it releases said first cam (18) , said release means (8) being connected to said second cam

(19) to move the latter between said blocking and releasing positions.

4. The actuating device (1) according to claim 3, wherein said first cam (18) is elastically biased to the blocking position.

5. The actuating device (1) according to claim 3 or 4, wherein said release means (8) comprise first release means to release said second cam (19) under regular actuating conditions and second release means to be capable of releasing said second cam (19) under failure conditions .

6. The actuating device (1) according to any preceding claim, wherein said lifting unit (3) comprises a pneumatic main cylinder-piston unit (10) with said lifting ^'member (4) .

7. The actuating device (1) according to claim 6, wherein said first release means comprise a release cylinder-piston unit (25) in communication with said main cylinder-piston unit (10) and connected to said second cam (19) such that an operation of moving downward said main cylinder-piston unit (10) entails a movement of releasing said release cylinder-piston unit

(25) , while an operation of moving upward and/or an absence of supply to the main cylinder-piston unit (10) entails- a blocking positioning of the release cylinder- piston unit (25) suitable to hold said second cam (19) in the blocking position.

8. The actuating device (1) according to any claim 5 to 7, wherein said second release means comprise cable means connected to said second cam (19) as well as to a lever (27) that interacts with an emergency valve (33) for the main cylinder-piston unit (10) such that, in response to an operation of the cable means, the emergency valve (33) empties the main cylinder-piston unit (10) and the second cam (19) releases the first cam (18) and thus the lifting member (4) .

9. The actuating device (1) according to claim 8, wherein said cable means comprise a cable (30) that passes through said release cylinder-piston unit (25) in a substantially coaxial manner.

10. The "actuating device (1) according to any claim 5 to 9, wherein said second release means comprise one or more emergency handles (36) being connected to said lever (27) by means of emergency cables (37) .

11. The actuating device (1) according to any preceding claim, wherein said blocking means (7) comprise selective blocking means suitable to prevent the door (2) from being opened manually when the vehicle speed is higher than a minimum speed.

12. The actuating device (1) according to claim 11, wherein, said selective blocking means comprise a single- acting pneumatic safety cylinder (39) , with a stem (40) that, by being caused to move outward when said minimum speed of the vehicle is exceeded, engages said second cam (19)^' such as to hold the latter in the blocking position.

13. The actuating device (1) according to any preceding claim, wherein said support structure (5) comprises a substantially L-shaped plate (14) which is connected to said main cylinder-piston unit (10) .

14. The actuating device (1) according to claim 13, wherein said auxiliary support plate (16) is connectable or connected to said substantially L-shaped plate (14) at a side edge of the substantially L-shaped plate (14) .

15. An auxiliary support device (9) which is removably connectable to an actuating device (1) for a door (2) of a vehicle, particularly a bus, said actuating device (1) comprising: - a support structure (5) , comprising means (6) for connecting the actuating device (1) to said vehicle; - a door-lifting unit (3) connected to the support structure (5) and comprising a lifting member (4) movable between a lifted position and a lowered position, and that can be connected to said door (2) , such that said upward and downward movement results in a closing and opening movement of the door (2) , characterized in that blocking means (7) suitable to block said lifting member (4) in the lifted position and release means (8) suitable to release the blocking means (7) in order to allow the lifting member (4) to move downward^' are connected to said auxiliary support device (9) •

16. The auxiliary support device (9) according to claim 15, comprising a substantially plane auxiliary support plate (16) .

17. The auxiliary support device (9) according to claim 15 or 16, wherein said blocking means (7) comprise a first cam (18) movable between a blocking position, in which it engages the lifting member (4) in order to block the latter in the lifted position, and a release position in which it releases the lifting member (4) , and a second cam (19) movable between a blocking position, in which it engages the first cam (18) in order to lock the latter in the blocking position thereof, and a release position, in which it releases said first cam (18) , said releasing means (8) being connected to said second cam (19) to move the latter between said blocking and releasing positions.

18. The auxiliary support device (9) according to claim 17, wherein said first cam (18) is elastically biased to the blocking position.

19. The auxiliary support device (9) according to claim 17 or 18, wherein said release means (8) comprise first release means to release said second cam (19) under regular operating conditions and second release means to be capable of releasing said second cam (19) under failure conditions.

20. The auxiliary support device (9) according to any claim 17 to 19, wherein said first release means comprise a release cylinder-piston unit (25) that can be in communication with a pneumatic main cylinder-piston unit (10) of said actuating device (1) and which is connected to said second cam (19) such that an operation of moving downward said main cylinder-piston unit (io) entails a movement of releasing said release cylinder- piston unit (25) , while an operation of moving upward and/or an absence of supply to the main cylinder-piston unit (10) entails a blocking positioning of the release cylinder-piston unit (25) suitable to hold said second cam (19) in the blocking position.

21. The auxiliary support device (9) according to claim

20, wherein said second release means comprise cable means connected to said second cam (19) as well as to a lever (27) that interacts with an emergency valve (33) for the main cylinder-piston unit (10) such that, in response to an actuation of the cable means, the emergency valve (33) empties the main cylinder-piston unit (10) and the second cam (19) releases the first cam (18) and thus the lifting member (4) .

22. The auxiliary support device (9) according to claim

21, wherein said cable means comprise a cable (30) that passes through said release cylinder-piston unit (25) in a substantially coaxial manner.

23. The auxiliary support device (9) according to any claim 19 to 22, wherein said second release means comprise one or more emergency handles (36) that are connected to said lever (27) by means of emergency cables (37) .

24. The auxiliary support device (9) according to any claim 15 to 23, wherein said blocking means (7) comprise selective blocking means suitable to prevent the door (2) from being opened manually when the vehicle speed is higher than a minimum speed.

25. The auxiliary support device (9) according to claim 24, wherein said selective blocking means comprise a single-acting pneumatic safety cylinder (39) , with a stem (40) that, when it is caused to move outward when said minimum speed of the vehicle is exceeded, engages said second cam (19) such as to hold the latter in the blocking position.