Telescopic aerial work platform

Abstract

 It refers to a telescopic aerial platform (10) adapted to be connected with a motor vehicle (A), and comprising a frame (12) adapted to be fixed on a motor vehicle (A), an upper telescopic system (18), rotating means (20) which are connected with the frame (12) and on which an end of the upper telescopic system (18) is fixed so that the upper telescopic system (18) can rotate in relation to the frame (12), and a platform (22) connected with the free end of the upper telescopic system (18).
The upper telescopic system (18) is inclinable in relation to the rotating means (20) by means of first moving means (56). The platform (22) comprises inclination adjusting means (74, 76) keeping said platform (22) at the same inclination in relation to the frame (12) as the inclination of the upper telescopic system (18) varies.

Description

[0001] The present invention refers, in general, to a telescopic aerial work platform, namely, a telescopic platform adapted to be mounted on a vehicle. More particularly, it is a telescopic platform showing particular features and adapted, for instance, to overcome difficult obstacles.

[0002] As is known, there exist several typologies of telescopic platform to be mounted on a motor-lorry or a dedicated vehicle or a railway wagon to allow an operator to perform a work at height.

[0003] The telescopic platforms according to the known art usually comprise a telescopic arm which is connected with the vehicle so as to vary its inclination in respect to the ground. A platform for the operator is fixed on the free end of the telescopic arm.

[0004] The telescopic platforms could comprise a fifth wheel to be interposed between the vehicle and the telescopic arm to allow the telescopic arm to rotate and to improve the possibilities of maneuver. Further improvements have been reached by utilizing arms of a fixed length o telescopic arms, articulated with each other.

[0005] In addition, stabilizers are in use to be arranged at the four corners of the vehicle to support the weight of the vehicle. These stabilizers allow to reach work positions out of the outline of the vehicle.

[0006] A telescopic platform according to the known art usually operates according to a first maneuver of lifting of the telescopic arm, a second maneuver of rotation in the wished direction and a third maneuver of extraction of the telescopic arm to reach the wished work area with the platform.

[0007] If, in addition, the system comprises articulated arms, its movements are consequently more complex since it is necessary to perform not only the above-mentioned maneuvers but also the relative rotations among the various articulated arms in order to reach a generic work area.

[0008] In an attempt to overcome a generic obstacle such as a building, a tree or a wall, the visibility for the operator in the platform could be limited and the operator could not be able to correctly ascertain the encumbrance of the whole telescopic system or the encumbrance of the articulated arms, there being thus a risk of interferences and impacts of parts of the telescopic platform in motion with the obstacles, especially in areas in which the operator has no visibility. In fact, the telescopic platforms according to the known art do allow to overcome an obstacle but the risk of moving the machine in a situation of imperfect visibility remains since the obstacle itself prevents to visualize and control any interference and impact of parts of the machine in motion with obstacles in areas that the operator does not see.

[0009] An aim of the invention is to carry out a telescopic platform that overcomes any obstacle in an easy and safe way.

[0010] A further aim of the invention is to carry out a telescopic platform that overcomes an obstacle on limiting as much as possible the risk of collision between parts of the machine and non-visible obstacles.

[0011] The above mentioned aims and further ones are reached according to the invention through a telescopic aerial platform adapted to be connected with a motor vehicle, an upper telescopic system, rotating means which are connected with the frame and on which an end of the upper telescopic system is fixed so that the upper telescopic system can rotate in relation to the frame, a platform connected with the free end of the upper telescopic system; the upper telescopic system being inclinable in relation to the rotation means by means of first moving means; the platform comprising inclination adjusting means keeping said platform at the same inclination in relation to the frame as the inclination of the upper telescopic system varies. The telescopic aerial platform is characterized in that said rotating means are connected with the frame through a lower telescopic system which is inclinable in relation to the frame by means of second moving means.

[0012] The telescopic aerial platform comprises, therefore, two telescopic systems which are connected with each other through means of rotation, and each telescopic system in inclined in respect to the point in which it is fixed on the lower part. In this way, the lower telescopic system is inclined in respect to the frame and, consequently, to the vehicle with which it is connected; the upper telescopic system is connected with the means of rotation so as to tilt in respect to the means of rotation which, in turn, are fixed on the free end of the lower telescopic system.

[0013] The configuration of the platform according to the invention allows to climb over obstacles. At the same time, the telescopic platform operates at height and therefore, it allows to perform all the necessary operations for the work without moving non-visible parts of the machine. This peculiarity is not provided in the articulated machines according to the known art, in which the climbing-over problem is solved but the articulated arm is still rotated on the lower part, at the level of the motor-lorry so that the risk of collision with non-visible parts of the structure remains during the phase of rotation. Advantageously, the rotating means comprise third moving means adapted to keep said rotating means at the same inclination in relation to the frame as the inclination of the lower telescopic system varies.

[0014] In this way, the means of rotation always operate on maintaining the same inclination, in general parallel to the ground. Consequently, the upper telescopic system is more stable and even the platform for the operator is always maintained at the same inclination in respect to the frame and to the ground on which the vehicle rests.

[0015] In addition, the lower telescopic system is pivoted on a support fixed on the frame; the second moving means for moving the lower telescopic system in relation to the frame comprise a first piston and the base of the cylinder of said first piston is pivoted on the support and the free end of the rod of said first piston is pivoted on the lower telescopic system; the rotating means comprise a slewing ring, a triangle which is pivoted on the end of the lower telescopic system, and an upper turret on which the upper telescopic system is pivoted, and said triangle and upper turret can rotate to each other by means of the slewing ring (fifth wheel), and the triangle is inclinable in relation to the lower telescopic system by means of third moving means; said third moving means comprise a second piston and the base of the cylinder of said second piston is pivoted on the lower telescopic system and the end of the rod of said second piston is pivoted on the triangle.

[0016] In the so-described configuration, the coupling pin of the cylinder of the first piston, the coupling pin that couples the lower telescopic system with the support, and the coupling pin that couples the rod of the first piston with the lower telescopic system are the vertices of a first triangle; likewise, the coupling pin of the cylinder of the second piston, the coupling pin that couples the triangle with the lower telescopic system, and the coupling pin that couples the rod of the second piston with the triangle are the vertices of a second triangle; advantageously, said first triangle and said second triangle are similar to each other so as to create a controlled moving system for the various pistons.

[0017] Advantageously, the telescopic aerial platform according to the invention comprises a hydraulic system to control and adjust the first piston and second piston so that due to the similarity of the first triangle with the second triangle, an extension of the first piston involves a corresponding extension of the second piston, and the triangle and slewing ring, coupled with the same triangle, are always kept at the same inclination in relation to the frame, regardless of the inclination of the lower telescopic system.

[0018] Advantageously, the hydraulic system comprises a control valve connected with pumping means which pump oil under pressure and with an oil drain, a first balance valve controlling the extension of the first piston, a second balance valve controlling the extension of the second piston, a distribution group connecting the control valve with the first balance valve and second balance valve.

[0019] The hydraulic system provides that the first piston and second piston are connected in series so that in the extension phase of the first piston and second piston, the oil going out of the cylinder of the first piston flows into the cylinder of the second piston, and in the contraction phase of the first piston and second piston, the oil going out of the cylinder of the second piston flows into the cylinder of the first piston.

[0020] In addition, the first balance valve comprises first piloting means, adapted to control the oil flow going out of the cylinder of the first piston when the first piston is in its contraction phase, and the second balance valve comprises second piloting means, adapted to control the oil flow going out of the cylinder of the second piston when the second piston is in its extension phase; in this way, the rod of the first piston and the rod of the second piston move under control and not owing to their own weights or external loads on avoiding sudden movements so as to guarantee a complete safety for the operator in the platform on the free end of the upper telescopic system. Advantageously, the first piloting means are controlled out of the first balance valve, and the second piloting means are controlled out of the second balance valve, said first piloting means and said second piloting means being connected with the distribution group. In this way, the control of the extraction of the two rods is done from the outside and a better management of the movements and of possible oil leakages is obtained.

[0021] Advantageously, the distribution group comprises first regulating means to regulate the oil pressure, for instance calibrated throttling means, which are connected with the first piloting means, and second regulating means to regulate the oil pressure, for instance calibrated throttling means, which are connected with the second piloting means.

[0022] In addition, the lower telescopic system comprises at least two beams which are extractable one from another, the cross section of said beams comprising at least five sides. In this way, an improved stiffness to torsion of the beams and of the whole telescopic system is obtained.

[0023] Advantageously, the free end of at least a first beam comprises a projecting element adapted to be received in a homologous seat which is obtained in an end of a second beam from which said at least a first beam is extracted when said at least a first beam is received in the second beam. In this way, when the telescopic system is collapsed, an improved stiffness to torsion is guaranteed.

[0024] Further features and details of the invention will be better understood from the following specification, which is given as a non-limiting example, as well as from the accompanying drawings wherein:

Fig. 1 is a side view of a telescopic platform according to the invention, arranged in an opened configuration;

Fig. 2 is a detail of a perspective view of the telescopic platform in Figure 1, arranged in a different configuration;

Fig. 3 is a rear view of the telescopic platform in Figure 1, arranged in a closed configuration;

Fig. 4 is a side view in section of the telescopic platform in Figure 3, according to section plane in Figure 3;

Figures 5, 6 are axonometric views of a telescopic platform according to the invention, arranged in a closed configuration and in an intermediate configuration, respectively;

Fig. 7 is a side view of a telescopic platform according to the invention, arranged in an opened configuration;

Fig. 8 is a hydraulic diagram of a system of horizontal maintenance according to the invention;

Figures 9, 10 are details of the hydraulic diagram in Figure 8;

Figure 11 is a perspective view of a telescopic platform according to the invention, arranged in an opened configuration, the upper part being rotated orthogonally to the vehicle.

[0025] With reference to the accompanying drawings, in particular to Figure 1, number 10 denotes a telescopic platform which comprises a frame 12 which is adapted to be constrained to a motor vehicle A, a support 14 which is constrained to said frame 12, a lower telescopic system 16 which is pivoted to the support 14 and an upper telescopic system 18 which is constrained through a turret 20 to the lower telescopic system. A platform 22 is pivoted to the free end of the upper telescopic system 18.

[0026] Four telescopic stabilizers 13 are fixed on the four corners of the frame 12, respectively, to lift the motor vehicle A from the ground S.

[0027] The lower telescopic system 16 comprises a first beam 24 which is pivoted to the upper end of the support 14 and is moved by a hydraulic piston 26 which in turn comprises a cylinder which is pivoted to the lower end of the support 14 and a rod 30, the free end of the rod 30 being pivoted to the first beam 24. A second beam 32 is connected with the first beam 24 so as to slide and is extractable by means of a hydraulic piston 34 which comprises a cylinder 36 which is fixed on the first beam 24, and a rod 38 which is constrained to the second beam 32. Both the first beam 24 and the second beam 32 have an octagonal hollow section.

[0028] A pair of teeth 33 protrude from an end of the second beam 32. In the closed configuration of the articulated platform as represented in Figure 5, said teeth 33 are inserted in suitable seats which are obtained in the first beam 24 to improve the transmission of the stresses from the second beam 32 to the first beam 24.

[0029] As visible in Figure 2, the turret 20 comprises a triangle 40 which is pivoted at one end to the second beam 32 of the lower telescopic system 16. Said triangle is moved by a hydraulic piston 42 which comprises a cylinder 44 which is pivoted to the second beam 32, and a rod 46 which is pivoted at the free end to the triangle 40.

[0030] At the other end of the triangle 40, an upper turret 48 is constrained through a motorized slewing ring 50 so as to rotate. The slewing ring 50 allows a controlled relative rotation between the triangle 40 and the upper turret 48. As it appears from Figure 1, the upper telescopic system 18 comprises a first bar 52, which is pivoted to the upper turret 48, and a second bar 54, which is constrained to the first bar 52 so as to slide. Both the first bar 52 and the second bar 54 have a rectangular hollow section.

[0031] The first bar 52 is moved by a hydraulic piston 56 which comprises a cylinder 58 which is pivoted at one end to the upper turret 48, and a rod 60 the free end of which is pivoted to the first bar 52.

[0032] As it appears from Figure 2, a hydraulic piston 62 comprises a cylinder 64 which is constrained to the upper turret 48 so as to rotate and a rod 66 which is constrained to the first bar 52 so as to rotate.

[0033] The second bar 54 can be extracted from the first bar by means of a hydraulic piston 68 which comprises a cylinder 70 which is fixed on the first bar 52 and a rod 72 which is constrained to the second bar 54.

[0034] The free end of the second bar 54 comprises a body 55 which develops in a direction which is essentially orthogonal to the main development of the second bar 54 which shows, therefore, an essentially L-shaped conformation. An articulation 74, visible also in Figure 4, is constrained to the free end of the body 55 and is moved by means of a hydraulic piston 76 which comprises a cylinder 78 which is pivoted to the second bar 54 and a rod 80 which is pivoted to an end of the articulation 74.

[0035] The platform 22 is constrained to the opposite end of the articulation 74 so as to rotate and is moved as it appears from Figure 3 by means of a hydraulic piston 82 which comprises a cylinder 84 which is pivoted to the platform 22 and a rod 86 which is pivoted to the articulation 74.

[0036] The working of the telescopic platform 10 is described below.

[0037] As represented in Figures 4 and 5, the articulated platform has a closed configuration in which the lower telescopic system 16 is almost parallel to the frame 12 and rests on the frame 12; the second beam 32 is completely inserted in the first beam 24. The upper telescopic system 18 rests on the lower telescopic system 16, the second bar 54 being completely inserted in the first bar 52. Consequently, a positioning of the platform 22 is obtained near the ground.

[0038] If necessary, a rapid moving of the telescopic platform 10 is possible without awaiting the positioning of the stabilizers 13 since it is possible to maintain the stabilizers 13 in a closed position, that is a non-working position, by limiting the possible movements of the telescopic platform 10 in order to maintain the whole centre of gravity in the inside of the rectangle formed by the wheels of the motor vehicle A.

[0039] However, the positioning of the stabilizers 13 allows to control the movement of the upper telescopic system 18 with less limitations.

[0040] The telescopic platform 10 can be moved according to a first mode of utilization on maintaining the lower telescopic system 16 stationary as in the above-mentioned closed configuration by utilizing the hydraulic piston 56 to lift the upper telescopic system 18.

[0041] The hydraulic piston 76, which controls the movement of the articulation 74, is connected through a closed circuit with the hydraulic piston 62 which is constrained to the first bar 52 so as to rotate. When the first bar 52 is lifted, its lifting provokes directly the going out of the rod 66 of the hydraulic piston 62 which is pivoted to said first bar and provokes indirectly the reentering of the rod 80 of the hydraulic piston 76 which controls the movement of the articulation 74 and consequently, the inclination of the platform 22.

[0042] The identical constructive features of the two hydraulic pistons 62, 76 allow to maintain the inclination of the platform 22 in relation to a horizontal plane, regardless of the movement of the first bar 52.

[0043] Then, the upper telescopic system 18 is put in rotation by controlling the motorized slewing ring 50 so as to reach the wished angle of rotation.

[0044] The second bar 52 is extracted in relation to the first bar 52 by utilizing the hydraulic piston 68 so that the operator in the platform 22 can reach work areas at a middle height, the platform 22 being always horizontal in relation to the ground.

[0045] In this first mode of utilization, the stresses on the lower telescopic system 16, provoked by the lifting and rotation of the upper telescopic system 18 through the turret 20, are mainly torsion stresses and are discharged through the teeth 33 from the second beam 32 to the first beam 24.

[0046] The octagonal hollow section of the lower telescopic system 16 reacts thus to the stresses of the twisting moment much more than a rectangular hollow section, utilized in the telescopic platforms, produced according to the known art.

[0047] According to a second mode of utilization, as visible in Figure 6, the lower telescopic system 16 of the telescopic platform 10 is lifted by means of the hydraulic piston 26, for instance to put the lower telescopic system 16 in a vertical position as it appears from Figure 1 in order to obtain the lifting of the motorized slewing ring 50. Consequently, it is possible to turn the upper telescopic system 18 at height.

[0048] The movement of the hydraulic piston 26 is connected with the movement of the hydraulic piston 42 which works to maintain the plane of rotation of the motorized slewing ring (fifth wheel) 50 horizontal.

[0049] In addition, the movement of the hydraulic piston 34 provokes the extraction of the second beam 32 in relation to the first beam 24 so that the lower telescopic system 16 reaches the extended configuration as represented in Figure 7 and the platform 22 reaches the maximum height.

[0050] A system 100 for maintaining the motorized slewing ring (fifth wheel) 50 horizontal is described below.

[0051] The system for the horizontal maintenance operates through a particular construction of the lower telescopic system 16 and through a selection of the points in which the hydraulic pistons 26 and 42 are pivoted.

[0052] Indeed, the system for the horizontal maintenance takes advantage of the similarity between a first triangle B and a second triangle C, represented in Fig. 4.

[0053] The first two vertices of the first triangle B are the point in which the cylinder 28 is pivoted and the point in which the rod 30 of the hydraulic piston 26 is pivoted. The third vertex of the first triangle B is the point in which the first beam 24 is pivoted upon the support 14.

[0054] The first two vertices of the second triangle C are the point in which the cylinder 44 (visible in Figure 2) is pivoted and the point in which the rod of the hydraulic piston 42 is pivoted. The third vertex of the second triangle C is the point in which the triangle 40 is pivoted upon the second beam 32.

[0055] The similarity between the first triangle B and the second triangle C, as described previously, allows to maintain the motorized slewing ring (fifth wheel) 50 horizontal unless there occur offsets in the system or reduction in the volume of the oil that feed the hydraulic pistons 26 and 42 owing to the compressibility of the oil.

[0056] As it appears from Figures 8, 9, 10, the system 100 for the horizontal maintenance comprises a 4/3 valve 102 which in turn comprises two controls 104, 106, as visible in Fig. 10.

[0057] The 4/3 valve 102 is connected through a branch 108 with the line pressure, through an outlet branch 110 with the outlet and with two branches 112, 114 in the inlet.

[0058] In turn, the branches 112, 114 are connected with a distribution group 116 which comprises two pressure limiting valves 118, 120, four calibrated throttling elements 122, 124, 126, 128 and two manual taps 127, 129 which are normally closed and normally opened, respectively.

[0059] Four further circuit branches 130, 132, 134 and 136, two outer piloting branches 138, 140 and an outlet branch 142 are connected with the distribution group 16.

[0060] The circuit branches 134, 136 and the outer piloting branch 138 are connected with a balance valve 144 which comprises two non-return valves 146, 148, two control sections 150, 152, four inner branches 154, 156, 158, 160, and inner piloting element 162 and two inner pilot branches 164, 166. The balance valve 144 is connected through two circuit branches 168, 170 with the hydraulic piston 42.

[0061] The circuit branches 130, 132 and the outer piloting branch 140 are connected with a balance valve 172 which comprises two non-return valves 174, 176, two control sections 178, 180, four inner branches 182, 184, 186, 188, an inner piloting element 190 and two inner piloting branches 192, 194. The balance valve 172 is connected through two circuit branches 196, 198 with the hydraulic piston 26.

[0062] The lifting of the lower telescopic system 16 through the hydraulic piston 26 is done by actuating the control 106 of the 4/3 valve 102 which puts in communication the branch 108 under pressure with the branch 112 which in turn puts under pressure the inlet branch 130 of the distribution group 116, the manual tap 129 being opened normally. The calibrated throttling elements 122, 124 are arranged in series and are regulated so as to reduce the pressure between the upward duct and the downward duct of the calibrated throttling element 122 and to reduce further the pressure between the upward duct and the downward duct of the calibrated throttling element 124 in order to discharge oil in the discharge branch 142. In this way, the oil in the outer piloting branch 138 is at a lower pressure than the pressure of the circuit, for instance in the branch 130.

[0063] The manual tap 127, normally closed, prevents the passage of oil completely. Consequently, the oil under pressure in the branch 130 flows in the balance valve 172 and passes through the non-return valve 174 and inner branches 184, 182 and through the inner piloting element 190 which acts on the control section 180 and provokes the opening of same. Thus, the branch 196 is put under pressure and brings oil under pressure in the cylinder 28 of the hydraulic piston 26 in the bottom side on provoking the going out of the rod 30 of the hydraulic piston 26.

[0064] The going out of the rod 30 puts under pressure the branch 198 which is connected with the side of the rod of the hydraulic piston 26 and puts under pressure the inner branch 186 which does not communicate with the inner branch 188 owing to the presence of the non-return valve 176, and the inner piloting branch 194 which widens the opening of the control section 180 by putting the branch 198 in communication with the branch 132.

[0065] The branch 132 put under pressure only the branch 134 on passing through the distribution group 116 and putting thus under pressure the inner branch 156 of the balance valve 144 and, as described previously as regards the hydraulic piston 26, puts under pressure the branch 168 and provokes the going out of the rod 46 of the hydraulic piston 42.

[0066] The pressure, controlled through the calibrated throttling means 122, 124 of the distribution group 116, is lower than the pressure of the circuit. This lower pressure in the calibrated throttling means 122, 124 provokes the action of the outer piloting element 138 of the control section 152 so that the rod 46 of the hydraulic piston 42 is allowed to go out in a controlled way and not on account of its weight. In this way, it is possible to avoid the risk of a too rapid going out of the rod 46, which involves the formation of vacuums in the inside of the branch 168 and consequently, in the inside of the branch 134 and a consequent misalignment of the hydraulic pistons 26, 42 and a loss of similarity between the triangles B and C on causing an unwished loss of horizontality in the motorized slewing ring (fifth wheel) 50.

[0067] This function of the outer piloting means 138, which corresponds with that of the outer piloting means 140, is important for the control of the balance of the hydraulic piston 42; in fact, the so-described construction avoids that the extraction of the rod 46 takes place too rapidly. This effect is due to the fact that the hydraulic piston 42, like the hydraulic piston 26, is loaded with a considerable compression or traction depending on the configuration of the telescopic platform 10 during its utilization.

[0068] Thus, the rod 46 goes out of the cylinder 44 at the wished speed and opens the control section 152 and discharges the branch 136 which is put in communication through the 4/3 valve 102 with the discharge branch 110. The descent of the lower telescopic system 16 takes place through the actuating of the control 104 of the 4/3 valve 102 which puts in communication the branch 108 (under pressure) with the branch 114 which, in turn, puts under pressure the inlet branch 136 of the distribution group 116. The calibrated throttling elements 126, 128 act as the calibrated throttling elements 122, 124 and put the outer piloting means 140 at a lower pressure than that of the circuit. Thus, the oil under pressure in the branch 136 flows in the balance valve 144 and passes through the non-return valve 148 through the inner branches 160, 158 and the inner piloting means 162 which acts on the control section 150 and provokes the opening of same. The branch 170 is thus put under pressure and lets in the compressed oil in the cylinder 44 of the hydraulic piston 42 on the side of the rod 46 of the hydraulic piston 42 so that the rod 46 of the hydraulic piston 42 is forced to re-enter. The re-entering of the rod 46 puts under pressure the branch 168 which is connected with the side of the bottom of the hydraulic piston 42 and puts under pressure the inner branch 154 which does not communicate with the inner branch 156 for the presence of the non-return valve 146 and the inner piloting branch 164 which enlarges the opening of the control section 150 on putting the branch 168 in communication with the branch 134.

[0069] The branch 134 puts under pressure only the branch 132 since the manual tap 127 is normally closed, when passing through the distribution group 116 and puts the inner branch 188 of the balance valve 172 under pressure and, like the hydraulic piston 42, puts the branch 198 under pressure and compels the rod 30 of the hydraulic piston 26 to re-enter.

[0070] By regulating the calibrated throttling means 126, 128 of the distribution group 116 it is possible to control, like the piloting means 138, the outer piloting means 140 of the control section 178 on allowing the rod 30 of the hydraulic piston 26 to re-enter without any risk of a too rapid re-enter, which could create vacuums in the inside of the branch 198 and the branch 132 and even the branch 134.

[0071] In fact, even the hydraulic piston could be loaded through compression or traction according to the configuration of the telescopic platform 10 during its utilization with the risk of a too rapid re-enter of the rod 30 owing to the load of the weight of the telescopic platform 10; this drawback is avoided by utilizing the so-described construction even in this phase.

[0072] Thus, the rod 30 re-enters in the cylinder 28 at the wished speed and opens the control section 178 and discharges the branch 130 which is put in communication with the discharge branch 110 through the manual tap 129 and the 4/3 valve 102.

[0073] The presence of the two pressure limiting valves 118, 120 permits to balance any oil leakage in the outside or inside of the branch 134 which forms an intermediate chamber. These leakages would modify the situation of synchronism of the system so that it would not be possible to guarantee a perfect horizontality of the slewing ring (fifth wheel) 50. The inner pressures in the system 100 for the maintenance of the horizontality can be balanced again through the communication allowed by the two pressure limiting valves 118, 120.

[0074] The utilization of the balance valves having an out piloting means, as described, solves an important safety problem for the operator since the only utilization of inner piloting means in the balance valves provokes a staying of compressed oil in the branch 134. In case of rotation of the upper telescopic system 18 owing to the movement of the motorized slewing ring (fifth wheel) 50, the pressure of said oil causes an inversion of the load condition of the hydraulic pistons 26, 42 and could maintain a control section open in case of an inner piloting means on causing an unwished sudden, dangerous movement.

[0075] The only utilization of outer piloting means could cause the considerable drawback that the indirectly controlled hydraulic piston is not controlled during the balancing, namely, the hydraulic piston 42 during the lifting and the hydraulic piston 26 during the descent.

[0076] The presence of the calibrated throttling elements 122, 124, 126, 128 has thus permitted to improve the brake of the indirectly controlled hydraulic piston.

[0077] The slewing ring (fifth wheel) 50 is maintained horizontal so as to work in optimum conditions according to the specific rules for a good working and to allow a correct movement of the telescopic platform 10.

[0078] Should the platform 22 swing round a non-vertical axis, the platform 22 would have a variable work height which would vary with the variation of the swinging of the upper telescopic system 18.

[0079] In addition to the problem of the variable work height, there would be the problem of the non-horizontality of the platform 22 so that the operator would be compelled to work in an inclined platform 22 with the risk of falling down. As described above, the telescopic platform 10 enables the operator in the platform 22 to reach the wished work area by utilizing one of the two above-mentioned ways of utilization.

[0080] In the first way of utilization, the telescopic platform 10 is used as the platforms of the prior art in which the lower telescopic system 16 is maintained closed and nearly parallel to the ground.

[0081] In the second way of utilization, the telescopic platform 10 allows to advantageously bring at height the swinging of the upper telescopic system 18, controlled by the motorized slewing ring (fifth wheel) 50, as represented in Figure 11.

[0082] Thus, an operator in the platform 22 is able to overcome an obstacle such as a wall, a building, a tree etc. on maintaining the lower telescopic system 16 in a vertical position and controlling only the swinging of the upper telescopic system 18 and its inclination relative to the plane of rotation of the motorized slewing ring (fifth wheel) 50 without a risk of collision with fixed or movable obstacles near the lower telescopic system 16.

[0083] From the above description it appears that the lower telescopic system 16 according to the invention bears stresses which are different from the ones to be borne by the arms in the prior art.

[0084] In fact, the arms in the prior art are loaded only with a simple flexion which always has the same development as the inner stresses and therefore, a rectangular section is sufficient to bear said inner stresses which do not vary as regards their typology and direction by only their intensity while the stresses on the lower telescopic system 16 vary according to its inclination relative to the ground S and to the swing of the upper telescopic system 18 which stresses the lower telescopic system 16 with variable bending and twisting moments.

[0085] The resistant octagonal section of the lower telescopic system 16 is similar to a circular section and in the first way of utilization, its behavior remains uniform as the twisting moment varies and in the second way of utilization, its behavior remains uniform as the bending moment varies, the bending and twisting moments being variable in particular owing to the swinging movement controlled by the motorized slewing ring (fifth wheel) 50 while the rectangular section used in the prior art does not have a uniform behavior.

[0086] The platform according to the present invention comprises a compensation circuit which allows a re-alignment of the system in case of leaks which could provoke a lack of parallelism of the elements, as described above. In fact, since the lack of parallelism involves dangerous situations such as a risk of collision of the arm with the platform cabin, the platform control system comprises a back-up system which can stop those operations which could cause a condition of danger in case of a wrong working or when the horizontality of the system is not guaranteed.

[0087] In addition, further variants and modifications are possible, for instance the carrying out of a lower telescopic system 16 showing a circular section, but are to be considered as included in the scope of protection of the present invention as described in the following claims.

Claims

1. Telescopic aerial platform (10) adapted to be connected with a motor vehicle (A), comprising:

- a frame (12) adapted to be fixed on a motor vehicle (A);

- an upper telescopic system (18);

- rotating means (20) which are connected with the frame (12) and on which an end of the upper telescopic system (18) is fixed so that the upper telescopic system (18) can rotate in relation to the frame (12);

- a platform (22) connected with the free end of the upper telescopic system (18);

said upper telescopic system (18) being inclinable in relation to the rotating means (20) by means of first moving means (56); the platform (22) comprising inclination adjusting means (74, 76) keeping said platform (22) at the same inclination in relation to the frame (12) as the inclination of the upper telescopic system (18) varies;
characterized in that said rotating means (20) are connected with the frame through a lower telescopic system (16); said lower telescopic system (16) being inclinable in relation to the frame (12) by means of second moving means (26).

2. Telescopic aerial platform (10) according to claim 1, wherein the rotating means (20) comprise third moving means (42) adapted to keep said rotating means (20) at the same inclination in relation to the frame (12) as the inclination of the lower telescopic system (16) varies.

3. Telescopic aerial platform (10) according to claim 2, wherein the lower telescopic system (16) is pivoted on a support (14) fixed on the frame (12), wherein the second moving means (26) for moving the lower telescopic system (16) in relation to the frame (12) comprise a first piston (26) and the base of the cylinder (28) of said first piston (26) is pivoted on the support (14) and the free end of the rod (30) of said first piston (26) is pivoted on the lower telescopic system (16), and wherein the rotating means (20) comprise a slewing ring (50), a triangle (40) which is pivoted on the end of the lower telescopic system (16), and an upper turret (48) on which the upper telescopic system (18) is pivoted, and said triangle (40) and upper turret (48) can rotate to each other by means of the slewing ring (50), and the triangle (40) is inclinable in relation to the lower telescopic system (16) by means of third moving means (42), and said third moving means (42) comprise a second piston (42) and the base of the cylinder (44) of said second piston (42) is pivoted on the lower telescopic system (16) and the end of the rod (46) of said second piston (42) is pivoted on the triangle (40).

4. Telescopic aerial platform (10) according to claim 3, wherein the coupling pin of the cylinder (28) of the first piston (26), the coupling pin that couples the lower telescopic system (16) with the support (14), and the coupling pin that couples the rod (30) of the first piston (26) with the lower telescopic system (16) are the vertices of a first triangle (B), and wherein the coupling pin of the cylinder (44) of the second piston (42), the coupling pin that couples the triangle (40) with the lower telescopic system (16), and the coupling pin that couples the rod (46) of the second piston (42) with the triangle (40) are the vertices of a second triangle (C), said first triangle (B) and said second triangle (C) being similar to each other.

5. Telescopic aerial platform (10) according to claim 4, wherein a hydraulic system (100) is comprised to control and adjust the first piston (26) and second piston (42) so that due to the similarity of the first triangle (B) with the second triangle (C), an extension of the first piston (26) involves a corresponding extension of the second piston (42), and the triangle (40) and slewing ring (50), coupled with the triangle (40), are always kept at the same inclination in relation to the frame (12), regardless of the inclination of the lower telescopic system (16).

6. Telescopic aerial platform (10) according to claim 5, wherein the hydraulic system (100) comprises:

- a control valve (102) connected with pumping means which pump oil under pressure and with an oil drain;

- a first balance valve (172) controlling the extension of the first piston (26);

- a second balance valve (144) controlling the extension of the second piston (42);

- a distribution group (116) connecting the control valve (102) with the first balance valve (172) and second balance valve (144);

the first piston (26) and second piston (42) being connected in series so that in the extension phase of the first piston (26) and second piston (42), the oil going out of the cylinder (28) of the first piston (26) flows into the cylinder (44) of the second piston (42), and in the contraction phase of the first piston (26) and second piston (42), the oil going out of the cylinder (44) of the second piston (42) flows into the cylinder (28) of the first piston (26).

7. Telescopic aerial platform (10) according to claim 6, wherein the first balance valve (172) comprises first piloting means (140, 178), adapted to control the oil flow going out of the cylinder (28) of the first piston (26) when the first piston (26) is in its contraction phase, and wherein the second balance valve (144) comprises second piloting means (138, 152), adapted to control the oil flow going out of the cylinder (44) of the second piston (42) when the second piston (42) is in its extension phase so that the rod (30) of the first piston (26) and the rod (46) of the second piston (42) move under control and not owing to their own weights or external loads on avoiding sudden movements.

8. Telescopic aerial platform (10) according to claim 7, wherein the first piloting means (140, 178) are controlled out of the first balance valve (172), and the second piloting means (138, 152) are controlled out of the second balance valve (144), said first piloting means (140, 178) and said second piloting means (138, 152) being connected with the distribution group (116).

9. Telescopic aerial platform (10) according to claim 8, wherein the distribution group (116) comprises first regulating means (126, 128) to regulate the oil pressure, which are connected with the first piloting means (140, 178), and second regulating means (122, 124) to regulate the oil pressure, which are connected with the second piloting means (138, 152).

10. Telescopic aerial platform (10) according to any of the preceding claims, wherein the lower telescopic system (16) comprises at least two beams (24, 32) which are extractable one from another, the cross section of said beams (24, 32) comprising at least five sides.

11. Telescopic aerial platform (10) according to the preceding claim, wherein the free end of at least a first beam (32) comprises a projecting element (33) adapted to be received in a homologous seat which is obtained in an end of a second beam (24) from which said at least a first beam (32) is extracted when said at least a first beam (32) is received in the second beam (24).

Drawing