DESCRIPTION

"Electro-pneumatic coupling group for trailer trucks" [0001] . The present invention relates to the field of trailer trucks and in particular it refers to an electro- pneumatic coupling group between the trailer truck tractor and the trailer or semitrailer.

[0002] . As known, the tractor of such vehicles is provided with a fifth wheel having a radial slit suitable for receiving a pin that extends from the trailer. The pin-fifth wheel coupling gives the articulated connection between the tractor and the trailer allowing both a rotation and an inclination between the two portions of the vehicle.

[0003] . Besides the coupling of the pin, in order to tow the semitrailer it is necessary to connect all the pneumatic and electrical lines coming from the respective supplies present on the tractor to the utilities present on the semitrailer. For example, there may be provided a pneumatic line for supplying the cylinders or tanks interlocked to the braking devices, a pneumatic line for piloting or controlling the braking, a group of electrical lines for the brake control and another group of electrical lines for the other services on the semitrailer, such as braking with EDS, lights, fieldbus

electrical signal transmission system (for example CMT- BUS) .

[0004] . At present, spiral wound pipes and cables are used for connecting these lines which, extending, ensure the connection also when the semitrailer articulates and rotates even by 90° relative to the tractor. [0005] . In order to connect these cables and pipes, the vehicle driver, after carrying out the coupling manoeuvre, must get down from the driving cab, get on the tractor between cab and semitrailer, and manually make the connections .

[0006] . Of course, this operation is difficult and requires some time to be performed correctly. The need of performing it automatically therefore is much felt, preferably without the need for the driver to get down from the cab.

[0007] . In any case, the presence of these spiral pipes and cables requires special maintenance and makes the back portion of the tractor complex and cumbersome. [0008]. Some attempts have already been made for eliminating the presence of at least the electrical cables. For example, it has been proposed to make the electrical lines pass into the pin, which must therefore be made internally hollow. However, such solution has

caused an unacceptable weakening of the pin, due to the fact that it must withstand very high strains. [0009] . On the other hand, other solutions proposed have been found to be too complicated and expensive. [0010] . The object of the present invention therefore is to propose an electro-pneumatic coupling group for connecting the tractor to the trailer or semitrailer of a trailer truck, which should allow obviating the disadvantages mentioned above in a simple but effective manner.

[0011] . Such object is achieved , with an electro- pneumatic coupling group according to the following claims . [0012] . The details and advantages of the electro- pneumatic group according to the present invention will appear more clearly from the following description of some preferred embodiments, made by way of an indicative non-limiting example with reference to the annexed drawings, wherein: [0013]. Figure 1 'shows a trailer truck with coupled tractor and trailer;

[0014] . Figure Ia shows a view of the trailer only; [0015] . Figure 2 shows a perspective view of the electro-pneumatic coupling group according to the

invention;

[0016] . Figure 3 shows an axial section view of the coupling group in one embodiment;

[0017] . Figure 4 shows an enlarged section view of a portion of the coupling group in an embodiment variation;

[0018] . Figure 4a shows an enlarged view of a detail of the coupling group;

[0019] . Figure 5 shows a section view of a portion of the coupling group in another embodiment; [0020] . Figures 6 and 6a show two section views of a revolving pneumatic union of the coupling group;

[0021] . Figure 7 shows a perspective exploded view of an example of electrical connection between two portions of the coupling group; [0022] . Figure 8 shows a perspective exploded view of another example of electrical connection between the two portions of the coupling group;

[0023] . Figure 9 shows an axial section view of the electrical connection system of the previous figure; [0024] . • Figure 10 shows a top plan view of a portion of a fifth wheel and of the conveyor device according to the invention;

[0025] . Figure 11 shows a cross section view of the body of the conveyor device in the proximity of the

centre of the fifth wheel;

[0026] . Figure 12 shows a partial axial section view of the coupling group that shows an example of a way of fixing the pin to the trailer frame; [0027] . Figures 13-18 show top plan views of the coupling group in as many embodiment variations;

[0028] . Figure 19 shows an axial section view of the coupling group and of the relevant means for an automated electro-pneumatic connection; [0029] . Figure 20 shows an end view of the coupling group and of the connection means;

[0030] . Figure 21 shows a side view of the support means of the electro-pneumatic connector only;

[0031] . Figure 22 shows a longitudinal section view of the electro-pneumatic conveyor and of the relevant connector prior to their coupling;

[0032] . Figure 23 shows a top view of the electro- pneumatic conveyor and of the relevant connector prior to their coupling; [0033] . Figure 24a shows a side partial section view of the conveyor and of the connector prior to their connection;

[0034] . Figure 24b shows a side partial section view of the conveyor and of the connector during their

connection;

[0035] . Figure 24c shows connected conveyor and connector;

[0036] . Figure 25 shows a longitudinal section view of the end of the conveyor with an electrical plug;

[0037] . Figures 26a and 26b show an end view and a longitudinal section view of a connector suitable for connecting to the conveyor of the previous figure; and [0038] . Figure 27 shows an end view of the conveyor with an electrical plug in an embodiment variation.

[0039] . ' In said drawings, reference numeral 10 globally indicates a trailer truck consisting of a tractor 11 and a trailer 12. For their connection with possibility of rotation, one relative to the other, the tractor is provided with a fifth wheel 13 and the trailer with a pin 14 suitable for inserting in said fifth wheel 13. To this end, the fifth wheel exhibits a central hole 15 suitable for receiving pin 14 and a radial slit 16 for allowing the introduction of pin 14 in said central hole 15 following the approach of the tractor to the trailer.

[0040] . . Trailer 12 is provided with a frame 50 defining at the bottom a support surface 51 for fifth wheel 13. [0041] . Pin 14 has a lower portion 14' protruding from said support surface so as to insert into hole 15 of

fifth wheel 13 through the radial slit 16, and an upper portion 14" emerging from said support surface 51 and fixed at the top to an element 7 of frame 50 raised relative to said support surface 51. In other words, an interspace 52 is obtained around said upper portion 14" of pin 14 which is comprised between said support surface 51 and said raised element 7 of frame 50.

[0042] . According to one embodiment (figure 12) , the upper portion 14" of pin 14 is fixed, for example by screwing, to a plate 7 which in turn is screwed or welded to frame 50. Plate 7 may also be made in a single piece with pin 14.

[0043] . In the radial slit 16 of fifth wheel 13 there is seated an electro-pneumatic conveyor 4 suitable for carrying at least one electrical and/or pneumatic line, coming from tractor 11, in the proximity of pin 14 and of the support surface 51 of trailer 12 on fifth wheel 13. Being arranged in said slit 16, conveyor 4 is angularly constrained by fifth wheel 13. [0044] . The at least one electrical or pneumatic line coming from conveyor 4 reaches an electro-pneumatic distributor thanks to which it is brought into trailer 12 for supplying a relative utility. Said distributor 2 is shaped as a ring stiffly fixed to conveyor 4 and turnably

mounted about the upper portion 14" of pin 14. [0045] . ' In other words, the distributor ring 2 is seated above the support surface 51 of trailer 12 on fifth wheel 13, in interspace 52 obtained around the upper portion 14" of pin 14.

[0046] . In an advantageous embodiment (see, for example, figure 3) , the support surface 51 exhibits a window 51' about pin 14 and the distributor ring 2 is seated in said window 51' , at the same level as surface 51, so as to directly face conveyor 4.

[0047] . According to an embodiment (see for example figures .4 , 4a) , the distributor ring 2 is supported by and rotates on, balls 20, in turn seated in a seat 20' obtained in a disc 3 fixed to the upper portion 14" of pin 14, for example by screws 3' .

[0048] . In accordance with a preferred embodiment illustrated in the drawings, conveyor 4 and distributor 2 are suitable for carrying and guiding two pneumatic lines 100, 101 and a multipolar electrical line 6. For example, the pneumatic line 100 has a passage section of at least 75 mm ² and a working pressure of 10 bar for feeding the cylinders/tanks for braking. The pneumatic line 101 has a passage section of at least 30 mm ² and a working pressure of 10 bar for piloting the braking. The multipolar

electrical line 6 consists of a bundle of electrical cable 66 contained in and protected by, a sheath 66' . Said bundle of cables 66 consists for example of twenty- two electrical cables with a section equal to 1.5 mm ² , seven of which for braking and fifteen for various services, such as for example EDS braking, lights, fieldbus control lines, etc.

[0049] . The electro-pneumatic conveyor 4 exhibits a body substantially shaped as a parallelepiped that mainly extends in horizontal direction, or orthogonal to pin 14.

In the body of conveyor 4 there are obtained two channels

100a and 101a for the pneumatic lines 100, 101 and a passage 6a or the electrical cable 6.

[0050] . Channels 100a, 101a are connected to pneumatic lines 100, 101 coming from the tractor through unions 99. Said channels end with a vertical portion facing upwards, that is, towards the distributor ring 2.

[0051] . In accordance with an embodiment, conveyor 4 is screwed to ring 2 by screws 4 ' , so that the upper surface of conveyor 4, wherein channels 100a, 101a lead, goes in strict contact with ring 2. In the latter, vertical channels 100b, 101b are obtained in continuation of channels ^' 100a, 101a of the conveyor. The pneumatic seal between the channels of the conveyor and the respective

channels in the ring is ensured by O-rings 40 that work in compression when the two elements are screwed to each other .

[0052] . Each vertical channel 100b, 101b of the ring communicates with a respective annular groove 100c, 101c obtained in a surface of ring 2 facing the upper portion 14" of pin 14.

[0053] . In an embodiment, the height or thickness of the distributor ring 2 is used to obtain in the side surface two vertical channels and two respective annular grooves at different heights., so as to obtain two separate and independent paths for the two pneumatic lines.

[0054] . In another embodiment illustrated in figure 5, wherein the upper portion 14" of pin 14 extends horizontally on at least a portion of ring 2, an annular groove 100c is obtained in the inner side surface of ring 2, whereas the other annular groove 101c is obtained in the upper surface of ring 2 overlapped by the upper horizontal portion 14" of pin 14.

[0055] . At the level of each of said annular grooves 100c, 101c, in the upper portion 14" of pin 14 there is obtained a hole 10Od, 101d that extends into said portion 14" so as to return the incoming fluid under pressure,

coming from the annular grooves of ring 2 , to respective outlets 10Oe, lOle preferably obtained in a zone of the side surface of portion 14" that is not surrounded by- ring 2 and that is therefore accessible for the connection to said outlets, through unions 99', of pipes 100', 101' directed to the trailer utilities. [0056] . The fluid and sealed continuity between the annular grooves 100c, 101c of ring 2 and the respective holes 10Od, 101d of pin 14 is ensured by two pairs of O- rings 200 that, working compressed between the facing surfaces of ring and pin, delimit the respective pneumatic paths defined by said annular grooves and by the corresponding holes in the pin, insulating them from each other and from the exterior. [0057] . It should be noted that said O-rings 200 constitute dynamic sealing means, since one of the two surfaces between which they are held moves relative to the other. They are therefore made of a material resistant to the wear caused by the pin rotation relative to the distributor ring.

[0058] . Such solution of pneumatic connection between tractor and trailer is especially advantageous since, irrespective of the angular position of the first one relative to the second one, and thus of the rotation of

the pin, the pneumatic lines 100, 101, 100', 101' always remain stationary, and therefore it is not necessary to size their length for compensating the rotations between tractor ^" and trailer. In fact, lines 100, 101 on board of the tractor are fixed to conveyor 4, which is stationary relative to the pin since it is recessed into the radial slit 16 of the fifth wheel 13, whereas lines 100', 101' on board of the trailer extend from pin 14, which is integral with the trailer itself. In fact, what compensates the rotation between tractor and trailer is the revolving pneumatic coupling between ring 2 and the upper portion 14" of pin 14.

[0059] . It should be ¹ noted that the annular grooves 100c, 101c can equally be obtained in pin 14 rather that in ring 2. What is required is a sealed pneumatic connection between holes 100b, 101b in ring 2 and holes 10Od and 101d in the pin also when the pin rotates relative to the ring. [0060] . In accordance with an embodiment variation of pneumatic connection illustrated in figures 6, 6a, 13, 14, 17, pipes 100', 101' that feed the utilities of the trailer withdraw the fluid under pressure directly from the distributor ring 2 rather than from the upper portion 14" of pin 14, as in the previous case.

[0061] . In this embodiment variation, conveyor 4 remains unchanged whereas the structure of the distributor ring 2 changes, as is clear from figure 6. The latter, in fact, is suitable for supporting two revolving L unions 70 that at the bottom communicate with the respective channels 100a, 101a of the underlying conveyor 4 and to which pipes 100', 101' are connected by unions 99" . [0062] . Said revolving unions 70 comprise a hollow pin 70' inserted in the base of the ring at and in continuation of a respective channel 10Oa ₇ 101a, and a head 70" turnably fitted and sealed, for example thanks to a sealing element 71, on said pin 70' . [0063] . Advantageously, ring 2 in this variation of embodiment exhibits an L shape so that the revolving unions 70 are comprised within the overall height dimensions of ring 2.

[0064] . This embodiment of pneumatic connection has the advantage that it is not necessary to drill pin 14 at the upper portion 14". However, due to the rotation of the trailer relative to ring 2, it is necessary to provide a portion of pipe 100', 101' forming a loop for compensating such rotation. The possibility of rotation of the heads of the revolving unions 70 advantageously

allows said unions to be always facing the direction in which pipes 100', 101' extend.

[0065] . It is clear that the pneumatic connection between tractor and trailer could also be obtained as a combination of the two types described above, that is, providing a pneumatic channel that crosses the distributor ring, enters into pin 14 and protrudes therefrom, and a revolving union mounted on the distributor ring for the direct connection to the pipes that go to the utilities (figure 14) .

[0066] . With reference to the electrical connection between trailer and tractor, various embodiments may be provided also for this aspect of the invention. In all these embodiments, the electrical cables 66 coming from the tractor are gathered by conveyor 4 and returned therethrough on the distributor ring 2. Hence, the electrical cables 66, enclosed and protected by sheath 66', are sent to the trailer utilities. [0067] . In an example of embodiment illustrated in figures 4, 7, 13, 14, 15, the set of electrical cables 66 is inserted into conveyor 4 without the outer sheath 66' for increasing the flexibility and resistance to torsion of said bundle of cables 66. [0068] . Conveyor 4 has an opening 4a facing the

overlying distributor ring 2 through which the bundle of cables 66 protrudes from conveyor 4. At such opening 4a, ring 2 exhibits a through opening 2a through which said bundle of cables 66 leads above ring 2 to be branched to the utilities.

[0069] . Advantageously, opening 2a of the ring leads into an annular seat 22 having a C section facing outwards suitable for receiving cables 66 by a sufficient portion for following the maximum rotation of the trailer relative to the tractor. More in detail, downstream of the fold undergone by the bundle of cables 66 for entering the annular seat 22, said bundle of cables 66 can be enclosed again into sheath 66' and is kept into position into the annular seat 22 by a bracket 88 fixed to ring 2, for example by screws 88' .

[0070] . ^" Preferably, opening 2a in ring 2 is obtained at the end of a radial slit 23' wherein there is also seated a block 5 , fixed for example by screws 5' , to ring 2 , suitable for holding and guiding the bundle of cables 66 into the aligned openings 4a and 2a of conveyor 4 and ring 2.

[0071] . In an embodiment variation illustrated in figures 3, 5, 8, 9, 16, 17, 18, the bundle of cables 66 protruding from conveyor 4 through opening 4a inserts

into a revolving L union 61 carried by ring 2. In particular, ring 2 exhibits a flat radial expansion 23 wherein there is obtained a radial slit 23" ending with a semicircular end 23a aligned with opening 4a in conveyor 4. In said slit there is seated a block 5a, fixed to ring 2 for example by screws 5a' , having a semicircular surface that defines, along with end 23a of slit 23", a circular seat wherein base 61' of the revolving union 61 is turnably inserted. [0072] . Similarly to what described for the revolving pneumatic unions, union 61 is advantageously comprised within the overall height dimensions of ring 2.

[0073] . Also in this case, the bundle of cables 66 passes through the conveyor without sheath 66' , so as to make a bend substantially of 90° to protrude at the top from conveyor 4. In output from the revolving union 61 the bundle of cables 66 can be coated again with sheath 66' , which can for example be pinched and/or glued to the outlet of union 61 (figure 9) . [0074]. Block 5a guides the revolving union 61 and aids the latter to withstand the strains it is subject to. Actually, such strains are limited since they are only due to the bending resistance of cable 6 and to the torsion resistance of the bundle of cables 66 at the

point where these exit from conveyor 4 through opening 4a to insert into the revolving union 61.

[0075] . Also in the case of connection by revolving union 61, the initial portion of cable 6 can be secured to and follow, the outer surface of ring 2 by bracket 88. [0076] . The possibility of rotation of the revolving union 61 advantageously allows said union to be always facing the direction in which cable 6 extends into the trailer. [0077] . In both cases, due to the rotation of the trailer relative to ring 2, it is necessary to provide a portion of cable 6 forming a loop for following such rotation. Cable 6, after such initial loop portion, is fixed to the trailer frame by a second bracket 8 and from this still point it continues towards the utilities.

[0078] . Advantageously, in order to allow the assembly and removal of conveyor 4 and of the distributor ring 2, window 51' obtained in the trailer support surface 51 to fifth wheel 13 exhibits such a width as to allow the extraction from and the introduction into the trailer of the entire conveyor-pin-distributor group, also assembled.

[0079] . Preferably, in such embodiment the space of window 51' comprised between frame 50 and ring 2 is closed at the bottom by a cover 9, for example made of

two halves screwed to frame 50.

[0080] . Such solution therefore allows screwing pin 14 to plate 7, for example by flared head screws 7' (figure 3) , and then completing the assembly of pneumatic pipes and electrical cables. Cover 9 in two halves can be easily removed even with conveyor 4 connected. Moreover, part of the loads of the thrust that pin 14 must withstand can be relieved on cover 9, and thus on frame 50. In other words, the strain is transmitted to the upper portion and to the lower portion of frame 50, that is, it distributes on all the section of the frame itself. [0081]. In an embodiment, pipes 100' , 101' exiting from distributor ring 2 of from the upper end 14" of pin 14, are guided between cover 9 and plate 7 by rolls 199 that freely rotate on pins 199' fixed to frame 50. Said rolls 199 can also be used for guiding the electrical cable 6. Freely rotating on pins 199', rolls 199 keep the pneumatic pipes and the electrical cable conveyed on the provided paths without damaging them. [0082] . In accordance with an advantageous embodiment (figure 18) , conveyor 4 and distributor 2 are further kept into a fixed angular position by an elastic element 120 acting in traction on ring 2 and anchored to frame 50, for example through return rolls 120' .

[0083] . As an alternative or in addition to the elastic element 120, the distributor ring 2 is associated to a radial pin 122 suitable for engaging into locks 123 integral with frame 50 of the trailer for preventing the rotation thereof relative to the distributor beyond a certain angle, for example 105°.

[0084] . It should be noted, in fact, that while in the presence of the tractor the trailer cannot normally rotate for more than 90° as it knocks against the cab, when it is parked it could rotate more, thus straining the electrical cable 6 and pipes 100, 101. The presence of the radial pin 122 and of locks 123 therefore prevents the occurrence of this situation. [0085] . Innovatively, therefore, the electro-pneumatic coupling group according to the invention allows using the free space necessarily present behind the pin seat in the fifth wheel inlet. Such free space is used for channelling the pneumatic and electric lines, containing the means guiding them, reaching the position close to the centre of rotation and passing beyond the trailer support surface on the fifth wheel.

[0086] . The overall height dimensions of the coupling group are very small, since the space used is comprised between the support surface on the fifth wheel and the

plate that is welded or screwed to the trailer frame and that is used to fix the pin to the frame itself. [0087] . It should be noted that the electrical and pneumatic lines are the same used in traditional connecting systems. In fact, the coupling group proposed herein allows less wear of the cables and safer operation, since the movement of rotation due to the articulation between tractor and trailer is not transmitted to the electrical and pneumatic lines that remain stationary. [0088] . In other words, the position of the electrical and pneumatic connections relative to the fifth wheel does not change.

[0089] . According to another aspect of the invention, the coupling group proposed herein is suitable for automating the operations for coupling and disconnecting the trailer from the tractor. In other words, it is possible to make the connection of the electrical and pneumatic lines between tractor and trailer without the need for vehicle driver of leaving the driving seat . [0090] . The coupling group in the embodiment illustrated in figures 19-27 allows achieving such objective.

[0091] . in this embodiment, the electro-pneumatic conveyor is provided with at least one multipolar

electrical plug 306 and with two prods 300, 301 for the connection to pipes 100, 101.

[0092] . Prods 300, 301 are screwed to conveyor 4, at the inlet of channels 100a, 101a. On the outer diameter, the two prods 300, 301 are fitted with an annular seal 302 that ensures the seal when the two prods couple to the pneumatic connection described hereinafter. [0093] . Examples of possible circular or rectangular electriqal plugs 306 are shown in figures 25, 26a-26b and 27. An electrical cable 66 branches from every single pin 306' of the plug that crosses conveyor 4 to reach distributor 2.

[0094]. Fifth wheel 13, below and at the sides of slit 16, is fixed to a support 310 to which at least one lever 311 is hinged, preferably two side levers 311, movable between a lowered rest position and a raised coupling position. In the proximity of the free end of said levers 311 there is hinged a connector holding plate 312. When levers 311 are in lowered position, plate 312 rests on a bracket 313 of support 310 and is also in a lowered position relative to conveyor 4. When levers 311 are moved to raised position, they move plate 312 to a raised position aligned with conveyor 4.

[0095]. The movement of levers 311 is carried out by

respective actuating cylinders 315 fixed to support 310. [0096] . Plate 312 is normally held in abutment on bracket 313 by springs 316 anchored to the end of levers 311. [0097] . Plate 312 carries an electro-pneumatic connector 320 provided with female pneumatic connectors 321 suitable for receiving prods 300, 301 and with at least one electrical tap 322 suitable for receiving a corresponding electrical plug 306. [0098]. ^" Connector 320 is thus connected to pipes 100, 101 and to the electrical cable 6 coming from the tractor cab.

[0099] . Connector 320 is movable between an inactive retracted position and an extended connection position, wherein prods 300, 301 and plugs 306 are steadily inserted in connectors 321 and in taps 322. For its movements, connector 320 is associated to a respective actuating member 325, also mounted on plate 312.

[00100] . When plate 312 is in lowered position and connector 320 is in retracted position, its front side facing conveyor 4, or that wherein the electro-pneumatic connections are obtained, abuts against a vertical wall 326 of support 310, acting as protective barrier for said connections against external agents.

[00101] . In accordance with an advantageous embodiment, the actuating member 325 acts on connector 320 through a square 330. The horizontal side of this square 330 ends at the front with a coupling end 331 suitable for engaging in a corresponding undercut 332 obtained in the front portion of the bottom of connector 320. [00102] . At the back, or at the side opposite undercut 332, connector 320 exhibits a tab 333. [00103] . Vertical tongues 334 extend from plate 312 wherein there is obtained a recess 335 suitable for receiving the back tab 333 of connector 320. [00104] . In the practice, when the actuating member 325 holds connector 320 in retracted position coupling it at the front through the coupling between the coupling end 331 and undercut 332, connector 320 does not abut at the back against the vertical wall of square 330 but remains separate therefrom due to the presence of tab 333 inserted in recess 335.

[00105] . Advantageously, support 310 is further associated to an oscillating safety lever 340 suitable for acting on the back portion of connector 320 when it is coupled to conveyor 4, for example stressed by a spring 342, preventing the extraction thereof even during jolts transmitted by the road irregularities during the

drive .

[00106] . Advantageously, moreover, prods 300, 301 and electrical plugs 306 are seated in a box seat 350 that extends at the back from conveyor 4 and that is suitable for receiving and guiding connector 320.

[00107] . The automated coupling and disconnection of the electro-pneumatic connections are managed by a central control unit that performs the following operations . [00108] . At first, the pair of levers 311 and therefore the connector holding plate 312 are in idle lowered position. Connector 320 is in retracted position, held by square 330 and with tab 333 in recess 335 of tongues 334.

Connector 320 is protected by wall 326.

[00109] . After the tractor has coupled the trailer, or after pin 14 has been inserted into fifth wheel 13, the actuating cylinders 315 pull levers 311 and therefore plate 312. At that point, connector 320 is aligned with conveyor 4, but still in retracted position.

[00110] . Actuating the actuating member 325 causes the advancement of square 330, which before contacting connector 320 for pushing it towards conveyor 4, shifts forward so as to release its coupling end 331 from undercut 332 of connector 320.

[00111] . When connector 320 has been pushed in depth

into the box seat 350 of conveyor 4, thus obtaining the electro-pneumatic coupling therewith, the safety lever 340 is free to lower engaging in the back portion of connector 320. [00112] . At that point, levers 311 and plate 312, with the actuating member 325, can be returned to the starting lowered position.

[00113] . To disconnect connector 320 from conveyor 4, the actuating member 25 is returned to raised position with square 330 in extended position. By raising, the actuating member 325 lifts the safety lever 340 freeing connector 320.

[00114] . At that point, the actuating member 325 retracts square 330, which couples connector 320 disconnecting it from conveyor 4. Connector 320 can thus be returned to retracted position and lowered to protected rest position.

[00115] . In this position, the inlet of the fifth wheel 13 is free again and pin 14 can be disconnected from the fifth wheel itself.

[00116] . It is clear that a man skilled in the art may make several changes and adjustments to the coupling group according to the present invention in order to meet specific and incidental needs, all falling within the

scope of protection of the invention as defined in the following claims .