Abstract:
The present invention relates to a coupling apparatus for the pivoted coupling of a vehicle having two vehicle sections, with coupling elements which are arranged to pivot towards each other, and which can be permanently coupled to a vehicle section. A brake arrangement operates between the coupling elements and forms an adjustable frictional grip between the coupling elements, which blocks the ability of the vehicle sections to pivot toward each other. In addition, the brake apparatus includes a hydraulic cylinder unit which operates on multiple radially acting brake elements.

Description:
FIELD OF THE INVENTION 
     The present invention concerns a coupling apparatus (hereinafter designated, “coupling”) to enable a joining of two motor vehicle units, wherein coupling comprises two mutually pivotal elements acting in a horizontal plane. The pivotal elements are installed, respectively, in each of the motor vehicle units and a brake arrangement is interposed between them in order to assure an adjustable frictional closure therebetween, so that an unwanted sway of one vehicle unit in reference to the other is restrained. 
     BACKGROUND OF THE INVENTION 
     Couplings of this type are already known in regard to commercial vehicles. A large number of designs have been published for couplings in tractor trailer design. 
     Customarily, a saddle mounted trailer equipped with such a coupling is attached to a tractor unit by a centrally positioned kingpin penetrating a support disk. This arrangement is referred to as a “fifth wheel”. A saddle connection consists of a coupling plate having a recess, into which a kingpin can be inserted and be locked against turning by a closure mechanism. The surface of the coupling plate defines the plane of slewing between a tractor and a trailer at the coupling level. At the same time, this surface is made frictional and upon which a plate encompassing the kingpin can safely rotate. In this way, the tractor and the trailer are bound together and enabled to turn about the kingpin. In the case of certain conditions of driving, especially where brake action occurs in sharp turnings, jack-knifing can occur, wherein the tractor and the trailer reach a minimum angle of closure together, so that the entire vehicle assembly is no longer controllable. A swinging of the trailer back and forth in increasing arcs can occur under some circumstances. Like problems are found with articulated busses, truck trailers and even conjoined rail cars. 
     A generally accepted concept is based on a principle that a saddle linkage is to be stiffened by a more or less strongly damped brake arrangement, i.e. by a an appropriate damping apparatus. U.S. Pat. No. 3,231,295 proposes, for example, a rotatable kingpin arrangement in the trailer connection, which exhibits its braking effect by a brake drum and a loop-type brake. The braking action is carried out, in this case, with a rod, which engages the motor vehicle brake assembly. U.S. Pat. No. 4,065,149 proposes a rotating, saddle plate installed on a tractor about a vertical axle. This saddle plate is to be turn-fast attached to the trailer extension by an oval kingpin. The rotation of the saddle plate can be restricted by an internally placed, pneumatic drum brake. The operation of this arrangement can be initiated by the brake system of the vehicle. GB 2 365 398 discloses a damping system interposed between the tractor and the trailer, which is intended to repress a tendency to jackknife. To accomplish this purpose, a hydraulic damping element is provided, the resistance of which is adjustable by opening and closing a compensation system. The damping can be carried out by either visco-electric or visco-magnetic means. 
     The damping here can have a relation to the angle posed by the tractor and trailer to one another, which may be measured by the relation of the brake action of the vehicle. U.S. Pat. No. 5,690,347 brings forth another concept, wherein the brake assembly operates with brake elements, which act simultaneously between the tractor and the trailer and are designed as eccentrically operating brake cylinders. GB 1 205 314, US 2005/0212256 A1 and DE 29 49 933 all present further ideas. 
     The demands made on a functional coupling apparatus are contradictive: first, it is necessary to create an enormous braking moment in order to restrain a jackknife effect, when one considers the weight of loaded tractor trailer units, which units are commonly used in commercial service. Second, a compact and space saving construction is required, so as not to interfere with payable volume, i.e. load, to be carried. The above cited concepts only partially fulfill the requirements. None of them dominate practical applications. A further demand is that a coupling having a brake system or may be easily mountable must be integrated into existing, standardized dimensioning. 
     BRIEF SUMMARY OF THE INVENTION 
     In consideration of the above, a purpose of the present invention is to make available an improved coupling, which better fulfills the above requirements and also to set aside, at least partially, the stated disadvantages. 
     The invention is characterized, in that an invented brake apparatus includes a single, cylindrical hydraulic unit, which acts on a plurality of radially acting braking elements. This construction is very compact and also enhances a required braking action. A multiplicity of hydraulic cylinders, acting respectively on an equal number of radially distributed brake elements can be assembled in a space saving form. The annularly encircling braking elements may operate by respective cylinder-piston arrangements. Thus, force is better transferred to each braking element with its braking surface, whereby a true frictional area can be optimally employed and loss from wear is reduced. Local variations in braking pressure are also reduced and efficiency is increased. 
     A single infeed fitting may be provided, through which hydraulic fluid enters and is apportioned by distribution lines to appropriate hollow cylindrical spaces. A system of this design is especially free of leakage, easily deaerated and reliable in operation. Embodiments may include an internally bored, interconnective, one-piece hydraulic unit, hereinafter designated as a “hydraulic block” which is especially compact and robust. Embodiments may also include four brake elements, which act at right angles to one another and are respectively driven by at least two cylinder-piston units. These are space saving and fit within the assigned space of an annular brake arrangement. 
     In yet other embodiments the hydraulic action may be increased by a power-multiplying linkage drive between the cylinder-piston elements and the brake elements. The drive may be designed as a connecting lever, which, by the linked binding between the cylinder-piston unit and the brake element, is particularly easy to engage and disengage. 
     Embodiments may include simple securement of a coupling by a standard steering wedge insertion in a saddle plate of a tractor. Such steering wedge arrangements are generally placed above the pivot center between the trailer and on a tractor mounted saddle plate. It is the purpose of the steering wedge arrangement to control the opposed inside-outside wheel sets of the trailer during driving turns. 
     Yet other embodiments may include a coupling, wherein the operating pressure from the hydraulic system can be directed to control the frictional connection between the two coupling elements. Such a control can increment working pressure into a multiplicity of control steps. Applications of this would be, for example, vehicle speed, departure angle between tractor and trailer, and rate of change of the departure angle. Also involved would be weight of tractor trailer, weight of load, steering angle and characteristics of brake action of the tractor. Values, corresponding to the above applications allow vehicle-specific action planning to be determined and adjusted by control. Sensors may be provided to capture these values, which sensors deliver the necessary data to the control system. For maintenance and supervision, control can be electronically bound to one or more display devices and/or operate automatic maintenance equipment where possible. This occurs advantageously by a so-called CAN-bus or by another field bus of equivalent design. A field bus is to have a standardized data transmission facility functioning to and from the control. 
     An articulated truck, in particular a tractor-trailer, a bus, or a rail mounted coach may include a coupling in accord with the above cited claims. 
     An embodiment of the invention is explained and described in greater detail with the aid of a drawing. There is shown in: 
    
    
     
       BRIEF SUMMARY OF THE DRAWINGS 
         FIG. 1  a view from below of an invented coupling, 
         FIG. 2  a view from the rear side of the coupling of  FIG. 1 , 
         FIG. 3  a cross-sectional view of the coupling of  FIG. 1  (Sec A-A in  FIG. 6 ), 
         FIG. 4  a sectional view of the coupling of  FIG. 1  (Sec. B-B), 
         FIG. 5  an exploded view of the coupling of  FIG. 1 , 
         FIG. 6  a view from above, showing the coupling of  FIG. 1 , 
         FIG. 7  a presentation in a plurality of views and sections of a hydraulic cylinder block from the coupling views of  FIGS. 1 to 6 , 
         FIG. 8  a view from above of an alternative embodiment of an invented coupling, and 
         FIG. 9  a block diagram of a control for an invented coupling. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIGS. 1 to 6  present an embodiment of the present invention, wherein, the assembly and the function of an invented coupling apparatus is demonstrated. 
     Statements in the following text regarding directions and locations, such as forward, behind, above, right and left, serve for the positioning of parts of the assembly of the coupling in a vehicle, relative to the forward driving direction and which assembly is in a certain section of an articulated vehicle. The objects positioned lie behind and out of sight of the driver, who sits forward thereof. 
     The underside of the coupling assembly  1 , as shown in  FIG. 1 , shows the bottom of the pivoting plate  2 , onto which the kingpin is turn-fast affixed thereto by circularly disposed bolts  4 . That is to say, the pivoting plate  2  turns with the kingpin  6  and vice versa. To this pivoting plate  2  is attached a steering wedge  8 . The pivoting plate  2  turns in bearings in the carrier plate  10 . The carrier plate  10  is fastened, preferably by welding, to the (not shown) chassis of the trailer. The pivoting plate  2 , is centered by the kingpin in a recess of a coupling plate (not shown) and is subjected to horizontal forces which arise between the tractor and the trailer. By the steering wedge  8 , the pivoting plate  2  is turn-fast connected to the coupling plate of a tractor (neither being shown). The steering wedge  8  is seated in a corresponding recess on the rear end of the coupling plate, whereby insertion and release of the kingpin  6  can easily be carried out. 
     The bottom of the pivoting plate  2  lies flatly against a next higher, facing surface of the coupling plate. Contrary to conventional vehicles with saddle mounted trailers, in the here depicted coupling  1 , in the case of road curve turning or maneuvering operations of the tractor-trailer combination, a simultaneous rotation between the pivoting plate  2  and the coupling plate does not occur. Rather, the rotation does occur between the pivoting plate  2  and the carrier plate  10 . This shift in rotation is due to the fact that the steering wedge  8  resists any turning deflection between the pivoting plate  2  and the coupling plate of the vehicle. 
     The bearing arrangement between the pivoting plate  2  and the carrier plate  10  is a turntable  12  (see  FIG. 5 ), which serves as a rotational bearing. This bearing arrangement is subjected to both tensile forces acting between the frame and the tractor in a horizontal direction as well as support forces acting in vertical directions. Accordingly, the outer ring  13  of the turntable  12  is affixed to the cover flange  15  by bolts  14  and the inner ring  16  is fastened by bolts  17  to the pivoting plate  2 . In a case of driving in a curve, or in maneuvering operations, with this arrangement, the tractor unit and the trailer can swing counter to one another while the pivoting plate  2  and the carrier plate  10  are turned against each other by the turntable  12 . 
     In order to restrict back and forth slewing of tractor and trailer, i.e., to brake the motion, the following is provided: in the interior of the carrier plate  10  is placed a hydraulic block (see  FIGS. 5 ,  6 ,  7 ). The block securement is of the force-fit type and effected by four support plates  20 . The support plates  20  are respectively affixed to the cover flange  15  by adjustment springs  22  and bolts  24 . By the hydraulic pistons  25 , the hydraulic block  18  acts on the brake blocks  26 , which move outward. The brake blocks  26  possess, on their outer surfaces frictional brake lining material  28 . 
     Upon the said slewing of the tractor-trailer sections, especially under non-braked conditions, the pivoting plate  2  will turn together with the inner ring  16  of the turntable  12  relative to the brake blocks  26  which function with the hydraulic block  18 , which is affixed to the carrier plate  10 . Upon a command for braking, the pistons  25  push the brake blocks  26  radially outward. The brake linings  28  frictionally engage the inside peripheral surfaces of the inner ring  16  and accordingly restrict rotating movement, according to such radial force as is available from the pistons  25 . The forces so engendered, are then directed, by the brake blocks  26 , which lie with their outer sides  29  on the corresponding side surfaces  27  of the support plates  20 , into the support plates  20  and from there through the adjustment screws  22  into the cover flange  15 , and thus into the carrier plate  10 , that is to say, into the saddle equipped trailer chassis. The turnable bearing arrangement is stiffened. Besides the load input in the cover flange  15 , the adjustment springs  22  have the function, with their inward extending end faces, of centering the mitered corners  30  of the hydraulic block  18  within the coupling assembly. 
     In the case of the embodiment of the present invention, the maximum braking moment is about 70,000 Nm and the pressure in the hydraulic system runs to some 420 bar. The hydraulic block  18  (see  FIG. 7 ) has an essentially square outline and is recessed in the middle section by opening  32 . By this opening  32 , it becomes possible for the hydraulic block  18 , in a space saving manner, to accept the anchoring socket  3  for the affixing of the kingpin  6  on the pivoting plate  2  (as seen in  FIG. 4 ). The hydraulic block is bored therewithin, by a peripherally running hydraulic passage  34 . 
     This passage  34 , consists of a plurality of intersecting hydraulic connections, these being through-drillings and dead-end borings. The resulting open ends of these borings are closed of with plugs of sealant  36 . Two feed borings  38  open the hydraulic passage  34  with hydraulic fittings  40 . 
     The hydraulic passage  34  runs through the upper zone of the hydraulic block  18  and intersects the base area of the cylinder openings  42 , within which the pressurized pistons  25  act in their piston-cylinder function. The hydraulic passage  34  intersects the cylinder openings  42  respectively in the inner and upper area, so that it forms the highest point in the hydraulic block  18 . This placement enables a reliable and safe fluid input and outlet in the hydraulic block for the hydraulic system, as well as an opening for the release of trapped air. This release of air is to be done prior to placing the equipment in operation. The pressurized pistons  25  run within their respective cylinders and are isolated by appropriate sealants  44  and possess properly positioned wipers  46 . 
     The hydraulic fittings  40  are connected with hydraulic lines  41 , which are connected to corresponding aggregates  64 ,  66  (see  FIG. 9 ). This fitting aids in deaeration of the hydraulic lines. 
     The coupling apparatus shown in  FIGS. 1-6 , possesses a hydraulic block as shown in  FIG. 7 , which acts upon four braking blocks  26  by two pistons  25 . 
       FIG. 8  shows a coupling arrangement  101 , wherein two hydraulic blocks  118  are provided. The hydraulic blocks act respectively on the cross ties  127   a , activated by two opposed hydraulic pistons  125 , which move in counter directions. By this activation, the cross ties  127   a , by brake force, act through cams  127   b  to move the brake block  126  with its brake lining  128 . Again in this case, the forces to which the brake lining  128  and brake blocks  126  are subjected are transferred to the corresponding support plates  120 , which are affixed to the cover plate  110 . In this arrangement, where two separate hydraulic blocks  118  are present, the situation is that the same principles (lever-transference) function as in the case with the single hydraulic block as is evident from  FIGS. 1-7 . 
     The invented brake action is controlled by rotational angularity. That is to say, the brake action becomes reinforced upon an increasing angularity between the pivoting plate  2  and the carrier plate  10 . At the same time, with an increase in swaying of the tractor and trailer units, the braking force becomes greater. Associated therewith, as  FIGS. 1-6  show, an analogous direction sensor  48  is combined with an eccentric shaped component  50  (see  FIGS. 5 ,  6 ). The eccentric piece  50  is coupled to the pivoting plate  2  and the directional sensor  48  reacts with the hydraulic block  18 . Between the active head of the directional sensor  48  and the eccentric piece  50 , a fissure-like open space is to be seen, which is defined by the peripheral surface  52  of the eccentric piece  50 , which faces the directional sensor  48 . The peripheral surface contour is designed in such a manner that, upon a turning of the eccentric piece  50  relative to the directional sensor  48 , the distance across the space changes. This change of the opening geometry of the space is detected by the directional sensor  48 . The signal, emitted on such an occasion, is “read” by control  60  (see  FIG. 9 ) as a corresponding sway or angular deviation of one tractor-trailer section relative to the other. The control result is that a regulation is imposed on the pressure which activates the pistons  25 . When this occurs, then a servo valve  64  (solenoid valve) and/or a hydraulic pump  66  is activated. 
       FIG. 9  shows a corresponding control  60  (see  FIG. 9 ) operating through a so-called CAM-Bus and is additionally connected to a display and service apparatus  62 . The control  60  is connected to a directional sensor  48  (determines angle of sway) and is also bound to a pressure sensor  54 , which samples in the passage  34  (see  FIG. 7 ) to determine available hydraulic pressure. A source of electric current V supplies the display/operational assembly  62  and provides the control system  60  with a potential of 10 to 32 volts. The control  60  is likewise connected with a pressure control valve  64 , which regulates the input pressure in the hydraulic line  41  and is supplied with hydraulic fluid by the motorized pump  66 . This fluid is subsequently fed to the hydraulic block  18 . The hydraulic motor is protected by a circuit breaker  68 , which is also communicates with the control  60 . Besides rotational angular signals from the sensor  48  and pressure signals from the pressure sensor  54 , the control  60  is enabled to pick up the additional signals from the CAN-bus interface. Such signals are delivered over the line G, for example, to the display-operational device assembly  62 . This display-operational device  62  possesses an indicator  70 , which shows the angle existing between the tractor and the trailer. Further, additional service elements  72  can be provided, so that various conditions of operation can be electronically interrogated and adjusted. Besides the CAN-Bus interface, it is also possible that other field bus connections can be realized. For example, these could be, but are not limited to: CANopen, Device Net, J1939, CLeANopen, LIN-Bus, KWP2000. The concept here used for control is not limited to a control system in the classical manner, but is intended to encompass regulation apparatuses wherewith the output braking power, which is related to hydraulic pressure, can be kept under control by a plurality of control circuits. For example, besides the already discussed regulated values and services such as slewing angle and change of velocity of the slewing, in addition, vehicle speed, pressure, total truck weight, load weight, and brake action of the tractor-trailer, can be considered singly or in their interaction. 
     Besides the above described embodiment(s) of the invention, wherein the coupling apparatus can be activated on a tractor-tailer by inserting the kingpin  6  through the coupling plates, there are also applications wherein the pivoting plate  2  is bolted or welded directly to the appropriate vehicle unit. Such embodiments are suited to application in articulated buses, truck trailers, and rail borne multi-car trains (such as street cars). 
     Further variations and embodiments of the present invention can be adapted by the expert within the limits of the following claims.