FR2595077A1 - IMPROVEMENTS ON ARTICULATED TRUCKS, ESPECIALLY SEMI-TRAILERS - Google Patents

Abstract

A SEMI-TRAILER OF AN ARTICULATED TRUCK HAS A REAR SUSPENSION 3 WITH TRAILING ARMS 8 CONTROLS BY AIRBAGS 10. THE BRAKES LOCK THE WHEELS 14 ON AXLES 11 THAT ARE FIXED TO THE TRAILING ARMS 8. IF THE HEIGHT OF THE SUSPENSION CHANGES THEN WHEELS 14 MAY ROLL ON THE GROUND, MOVING FORWARD OR REAR OF THE SEMI-TRAILER ASSEMBLY. THE STAND LOCATED AT THE FRONT OF THE SEMI-TRAILER HAS FEET, WHICH THEN ROLL ON THE GROUND, CATCHING THE MOVEMENT AND PREVENTING HIGH HORIZONTAL STRESSES FROM ACTING ON THE STAND.

Description

1. The present invention relates to articulated trucks

  and, more particularly, the semi-trailers of such trucks.

  The articulated truck semi-trailer generally has

  one or more pairs of wheels near its rear end and a stand on the front side, on which the semi

  trailer is supported when not attached to a trailer

  tor. The crutch is typically made up of a pair of jam-

  bes which can be folded telescopically and / or pivotally fixed to the body of the semi-trailer and / or retractable in another way so that it can be released from the ground

  when the semi-trailer is attached to a tractor.

  It has been proposed in the prior art to provide the extremi-

  lower tee of each leg of a means of coming into contact with the ground having the shape of a small wheel or a flat plate. If a flat plate is used, it can be pivotally connected to the leg so that it lies flat on a surface

  which is not level. In the United States patent

  that No. 2 926 889, there is provided a foot pivotally mounted with a surface coming into contact with the ground in the form of a convex arc of a cylinder, which is intended to tilt so as to 2. find a firm seat on sloping ground. To prevent the foot from acting in a roll, and consequently to prevent the semi-trailer from annoyingly changing position, this patent

  specifies that the center of curvature of the foot surface is

  -in contact with the ground must be above the pivot axis of the foot relative to the leg, hence a

self-centering action.

  In recent years, we have equipped semi-trailers

  air suspensions in which the wheels are mounted

  rotated at the ends of the axles, the axles are attached to thrust rods, the thrust rods are

  pivotally attached to the body of the semi-trailer at one end

  and the body of the semi-trailer rests on the other ex-

  hoppers of thrust rods via suspension

  pneumatic. When the semi-trailer is placed in

  parking brakes are applied to prevent the wheels from turning on their axles, so that the thrust rods, the axle and the wheels then act as a single rigid assembly pivotally connected to the

  trailer body and its position dictated by the suspension

pneumatic tire.

  A problem with an equipped semi-trailer

  air suspension is that the trailer can move

  forward or backward, when raising or lowering the suspension, in an amount equal to the vertical displacement of the vehicle. Raising or lowering the suspension

  may occur deliberately, or as a result of change-

  in the load applied to the trailer or as a result of air leakage, and the movement produced forward or towards

  the rear often results in the breaking of the classic legs

crutches.

  Note, therefore, that with a semi-trailer

  that equipped with an air suspension system such as

  described above, it is imperative to provide a means allowing

  both legs to move forward or backward 3. in a relatively free manner or at least a distance of the order of the maximum variation of the height can

  be due to the air suspension, so as to have the

  rance that the legs are not subjected to high bending stresses (they are designed to act practically only in compression). The use of wheels at the lower ends of the legs does not solve the problem since it is not practical to provide wheels with such a large radius of curvature or such a large contact area with the ground, and they tend to s '' embed in termacadam coverings to the point of not

be able to roll.

  The US patent No. 2,926,889 cited above does not describe the use of an air suspension on a semi-trailer and is therefore not concerned with the problem explained above allowing the legs to move towards

  forward and backward. In fact, this patent proposes an agency-

  which is specifically intended to ensure that when the stand is in operation, i.e. when the legs

  are lowered and support the front part of the semi-trailer

  that there will be no more danger than the "truck body", that is

  ie the body of the semi-trailer changes position even

  when the ground on which the semi-trailer is parked is tilted

  you. Therefore, the object of the patent is to provide

  lower legs half means that will avoid movement

  front and rear elements of the semi-trailer due to the slope of the ground, while the problem on which the present invention is focused is that of providing means at the lower ends

  legs that will allow movement forward and back

  trailer due to the operation of a system

  air suspension that can be the cause of such a

  even when the semi-trailer is placed on level ground. The present invention provides a semi-trailer which has wheels and a stand, in which means 4.

  defining the axes of rotation of the wheels are connected to the. cais-

  from the semi-trailer by push rods, and the kickstand

  the comprises one or more feet pivotally connected to the stand around axes which, at least when the stand is used, are substantially parallel to the axes of rotation of the wheels and have surfaces which come into contact with

  the ground which form convex arcs in a cross-sectional view

pendulum to the axes.

  It was by surprise that we found, -although the crutch-

  *! O the semi-trailer according to the present invention has a cons-

  somewhat similar to that of the American patent

  n 2 926 889, a solution to a problem which is totally different

  raise problems that this patent has faced and, with the advantage

  than what the said patent sought, which would be real-

  a disadvantage in a semi-trailer according to the present in-

  vention, does not appear to be important in practice.

  The semi-trailer stand can have two legs.

  bes which, at least when the stand is in use, are generally

  generally vertical and which each have a respective foot pivotally connected to its lower end. The length of the legs of the stand is advantageously adjustable, so that the

  feet can be lifted off the ground when not in use

  vice. In addition, some other means for retracting the legs may be provided. Each foot (or foot) can be pivotally connected to a leg by means of a pivot which is substantially centered on the longitudinal axis of the leg. Each pivot (or the pivot) may advantageously comprise a pivot axis, a central part of which is received in a rolling means with

  one end of the respective leg and whose ends op-

  posed are received in the rolling means on the foot rest-

  pectif. The bearings then do not need to be able to accommodate unbalanced loads, and may be lighter and less able to jam, which might otherwise be possible. Preferably, the rolling means mounted on the foot comprise a pair of cores, each extending between the pivot and an element defining the surface of the foot

coming into contact with the ground.

  The surface of the foot or of each foot coming into con-

  tact with the ground can be substantially located on a minor sector of an imaginary right circular cylinder whose axis is substantially parallel to the axis of the pivoting connection of the foot and the crutch. The axis of the swivel link is

  then advantageously located between the axis of the cylinder and the surface

  that of coming into contact with the ground, with an imaginary plane containing its two axes which pass substantially through the center of the surface of coming into contact with the ground. In this way,

  considerable savings can be made in

  re of weight and space, and to have a relative radius of curvature-

  large for surfaces coming into contact with the ground, without giving rise to a self-centering amplitude action

  sufficient to cause undesirable rolling resistance

vehicle.

  The semi-trailer may comprise a means resiliently urging each foot (or the foot) to put it in a position in which, in normal use, the ground is in contact with a central part of the surface coming into contact with the ground, advantageously a tension spring having one end fixed to the foot and the other end fixed to another part of the stand so that the extension of the spring is minimum when the foot is in said position. This has the effect of reducing any tendency of the feet to tip over when released from the ground and ensuring that they

  are in a central position when lowered

  on the floor. The push rods can be arms

dragged.

  The movement of the thrust rods relative to the body of the semi-trailer can be controlled by pneumatic suspension means disposed between a distal end of each rod and an element of the body and, as indicated above, the The present invention is particularly 6.

  useful when in this situation.

  The semi-trailer may include one or more

  sieux, each having a wheel rotatably mounted on each end and fixed on the intermediate parts of a pair of thrust rods.

  The present invention also provides an articulated truck

  culé comprising a semi-trailer according to the present invention

and a tractor.

  We will now describe two types of semi-trailers

  constructed according to the present invention, by way of example only

  Also, in conjunction with the accompanying drawings, in the

  which Figure 1 is a side elevational view of a semi-trailer; Figure 2 is a somewhat schematic side elevation view of an assembled rear suspension;

  Figure 3 is a front elevational view of a pre-

  semi-trailer stand leg shape; Figure 4 is a side elevational view of the first foot form; Figure 5 is a view similar to Figure 4, showing the foot moved; Figure 6 is a view similar to Figure-3 of a second form of the stand of the semi-trailer stand; and Figure 7 is a view similar to Figure 4 of the

second form of foot.

  In conjunction with the accompanying drawings, and

  at the beginning with FIG. 1, an embodiment of a semi-trailer

  that according to the present invention comprises a case represented

  tée in outline by the reference 1, a crutch

  semi-trailer indicated in outline by the

  ference 2, and tandem wheels with their respective suspensions, each suspension being represented in its

  outline by reference 3.

  The body 1 comprises a platform 4 supported by 7.

  un'faux-chassis 5 and has at its front end a device

  coupling pin 6 to connect the semi-trailer to a trailer

  tor (not shown) which may be conventional.

  Now in connection with Figure 2, each sus-

  assembled pension 3 comprises a pair of supports 7 fixed to the subframe 5, a pair being provided on each side of the semi-trailer. At each support 7, a trailed arm 8 pivots at its front end by means of a bearing 9. The bearings 9 allow the arms 8 to rotate relative to the body 1 of

  the semi-trailer around a horizontal axis which is perpendicular to

  the length of the semi-trailer and is common to the two trailed arms of the same suspension 3. A respective air bag 10 is arranged so as to act in compression upwards on the sub-frame 5 and downwards on the rear part of each arm 8, and is supplied with pressurized air by conventional means

  that we omitted to make the figure clearer.

  An axle 11 is fixed to the arms 8 of the suspension

  respective 3 by securing means 12, and cushioning

  weavers 13 extend between the securing means 12 and the supports 8. At each end of the axle 11 is rotatably mounted a wheel 14 and brakes (not shown) are arranged so as to cause the deceleration of the vehicle, or

  to immobilize the semi-trailer when it is parked

  by resisting or avoiding rotation of the wheels with respect to

axle port.

  As can be seen in Figures 1 and 2, most of the weight of the semi-trailer and its load (not shown) is transmitted to the ground via the wheels 14, and is transmitted to the wheels partly by through the bearings 9 and partly through the air bags 10

  and any variation in the degree of extension of the air bags 10 in-

  will cause a change in the height of the body 1 relative to the ground. As noted above, one can produce a

  such change of one of the airbags because the air is deliberate-

  deliberately introduced into or removed from the air bag, 8.

  or as a result of a variation in the compressive force acting

  health on the air of the bag by change of the load exerted

  on platform 4. The last cited cause occurs, naturally

  when a load is placed on or removed from the semi-trailer, and at times when the semi-trailer can

  be parked without a tractor, the semi-trailer

posing on his crutch.

  As noted above, when the vehicle is parked and the brakes are applied, the wheels 14

  cannot turn on axle 11 so that the wheels, the

  the god and the thrust rods 8 become in fact the same assembly

  ble rigid, and any variation in the air bags 10 can be taken into account by the pivoting of this assembly, forming a

  even everything with respect to body 1, around the axis of the rolls

  ments 9. As the wheels 14 rest on the ground under load, they will tend to roll instead of sliding on the ground and

  the entire rigid assembly formed by the wheels 14, the es

  god 11, and the thrust rods 8 will rotate and move along the ground with them. The axis of the bearings 9 will trace a trochoid path with its direction of movement relative to the ground perpendicular to a line connecting it to the point of contact of the wheels 14 with the ground. Thus, in the arrangement shown in Figure 2, the axis of the bearings 9 will move forward

  and down, or back and up in a di-

  rection inclined at approximately 450 with respect to the horizontal for the range of positions likely to occur in normal use.

  As, as explained above, the movement

  ment of the rigid assembly with respect to the body 1 is a

  tation around the axis of the bearings 9, the movement of this axis relative to the ground must be accompanied by an identical movement of the body relative to the ground. More precisely, the suspension rising or lowering, the contiguous part of the body 1 of the semi-trailer moves up and back or down and forward, respectively, 9.

  at an angle of about 45 from the horizontal.

  The front end of the semi-trailer is prevented from raising and lowering with the rear by the stand 2 (a slight resulting difference in the level between the ends of the semi may be taken into account trailer by a slight rotation

  body 1), but the front of the semi-trailer moves

  cera forwards and backwards over an approximate distance

  equal to the distance from the rear to

  forward and backward. Thus, as indicated above-

  the front end of the semi-trailer moves horizontally

  Lement along a distance which is approximately equal to the distance of upward or downward movement of the bearings 9 of the suspension, and this distance can typically reach mm. Now in connection with FIGS. 1 and 3 to 5, the

  stand 2 has a pair of telescopic legs 15 which can

  can be extended for use, or retracted for removal

  pledge from the ground when the semi-trailer is connected to a tractor

  by conventional means (not shown). At the lower end

  re of each leg 15 is a foot, represented broadly by the reference 16, which is pivotally fixed

  to the leg by a pin 17 received in a sleeve 18 welded to the

  lower leg tie and in a pair of bearings 19 my-

  tée on the foot. The axis 17 is substantially horizontal and perpen-

  perpendicular to the length of the semi-trailer.

  The foot 16 comprises a plate forming the sole 20 which has the shape of a straight circular cylindrical envelope sector with its axis 21 parallel to the axis 17. As shown in FIG. 4, the axis 21 of the plate 20, l axis 17, the center of gravity of the leg 16 and the center of the plate 20 are one above

  the other, in this order, in a common vertical plane.

  Foot 16 has an approximate pair of cores -

  sectoral 22 which are supported on the bearings 19 and whose arcuate lower edges abut against the inner surface of the plate 20. The cores-22 are supported 10.

  by flanges 23 extending outwards to the lateral sides

  rales, a transverse stiffener 24 covering the space between the cores at their centers, and longitudinal stiffeners 25

  rest against the insides of the lower edges of the cores 22.

  5. Spacers 26 connect pairs of flanges 23, covering the space between the cores 22, near their upper ends. As an example of suitable dimensions, the radius of curvature of the plate 20 can be 350 mm, the distance between the center line of the axis 17 and the center of the plate

  can be 250 mm, and the plate width can be 250 mm.

  As foot 16 is directly below leg 15, it

  is possible without requiring an abnormally heavy structure

  of, to distribute the load transmitted by the leg on a lar-

  larger foot gore than would be the case with a

  wheel, which should be offset to one side of the leg.

  In use, the foot 16 can hang on the leg and the stand 2 is lowered until the foot 16

  come in contact with the ground. At least on flat ground, neither

  calf, foot 16 is stable in the position shown in figure

  gure 4, with the center of the plate 20 directly below

leg 15.

  If you leave the semi-trailer with the stand 2 in

  the position shown in FIGS. 3 and 4, that is to say support

  both the front end and with the wheels 14 braked, and if the

  suspension height is subsequently changed, for example-

  ple by changing platform 4 or by unloading it, as explained above, the front part

  of the semi-trailer will move horizontally and the jam-

  bes 15 with them. Now in connection with FIG. 5, the

  plate 20 of foot 16 will tend to roll on the ground allowing

  both leg 15 to move forward or backward

  for example up to the position shown in Figure 5.

  As the plate 20 can have a greater effective width and a greater radius of curvature than this 11.

  would be practical with a conventional wheel, the foot 16 will have

  dance to sink into the tarmacadam or other sur- face coating

  relatively soft face and because of the larger radius of stroke

  bure, its rolling will be less hindered because it will have deformed the surface on which it rests, or by other small irregularities in the ground. Therefore, foot 16 will be able

  to roll while a conventional wheel would quickly

  dark. As the center of curvature 21 of the plate 20 is above the axis 17, at the moment when the foot 16 departs from the position shown in FIG. 4, the axis 17 rises from the ground and

  as a result, the self-centering action tends to oppose

  be on the move. However, it was found that the hori-

  zontales from the self-centering action are not sufficient

  to impose abnormally high constraints on

legs 15.

  Now in connection with FIGS. 6 and 7, the

  second embodiment of the foot, represented in its large

  lines by the reference 27, generally has the same structure

  re and the same function as the first mode 16, and for purposes

  conciseness, we will not repeat the description. Plate 28 of

  second embodiment of the foot 27 is wider than the plate

  than 20, and extends along a larger arc. The cores 29 are spaced, the pivot axis 30 and the sleeve 31 in which

  it is mounted are larger in line, and instead of flas-

  ques 23, of the transverse stiffening element 24, and spacers 26, there are spacers 32 in the center and 33 at the ends of the plate 28. A spiral spring 34 acts in

  tension between a support 35 welded to the sleeve 31 and a rod 36 -

  covering the space separating the two cores 29, urging the foot 27 to bring it into the central position shown

in figure 7.

  The present invention is not limited to the examples

  ples of realization which have just been described, it is on the contrary susceptible of modifications and variants which

will appear to those skilled in the art.

12.

Claims (11)

  1 - Semi-trailer comprising wheels (14) and a stand (2), characterized in that a means defining the axes of rotation of the wheels are connected to the body (1) of the semi-trailer by thrust rods (8) and the stand   is provided with one or more feet (16, 27) pivotally connected   lie with the crutch around axes which, at least when the   keel is in service, are substantially parallel to the axes of   rotation of the wheels and comprising surfaces (20; 28) of ve-   bare in contact with the ground which form convex arcs when   that we see them in a section perpendicular to the axes.   2 - Semi-trailer according to claim 1, character-   sée in that the stand (2) comprises two legs (15) which, at least when the stand is in use, are generally vertical and each of which comprises the respective foot (16; 27)   pivotally mounted on its lower end.   3 - Semi-trailer according to claim 2, character-   sée in that the length of the legs (15) of the stand is adjustable.   -20 4 - Semi-trailer according to any one of the res-   dications 1 to 3, characterized in that the foot or each foot (16; 27) is pivotally connected to one leg by a pivot (17;) which is substantially centered on the longitudinal axis of leg. -   5 - Semi-trailer according to claim 4, character-   sed in that the pivot or each pivot (17; 30) comprises a pivot axis whose central part is received in a rolling means (9) on an end part of the respective leg and whose opposite end parts are received   in the rolling means of the respective foot.   6 - Semi-trailer according to claim 5, character-   sée in that the rolling means (9) of the foot is provided on a pair of webs (22; 29) each of which extends from the pivot to an element defining the surface of the foot coming into contact with the ground. 13.   7 - Semi-trailer according to any one of the res-   dications 1 to 6, characterized in that the surface coming into   contact with the ground of the foot or each foot is located sensi-   wholly on a minor sector of an imaginary right circular cylinder whose axis is substantially parallel to the axis of the   pivoting connection of the foot with the stand.   8 - Semi-trailer according to claim 7, character-   sée in that the axis of the pivoting connection is between the axis of the cylinder and the surface coming into contact with the ground,   and an imaginary plane containing these two axes passes sensitive-   through the center of the surface coming into contact with the ground.   9 - Semi-trailer according to any one of the claims   tions 1 to 8, characterized in that it comprises a means (34) elastically urging the foot or each foot to bring it   in a position in which, in normal use, the central part   trale of the surface coming into contact with the ground is in contact with him.   - Semi-trailer according to claim 9, character-   in that the elastic biasing means (34) or each   elastic biasing means comprises a tension spring   sion (34) having one end fixed to the foot and the other extremi-   tee attached to another part (35) of the stand in such a way   the spring extension is minimum when the foot is ve in said position ..   11 - Semi-trailer according to any one of the claims   cations 1 to 10, characterized in that the push rods sée (8) are trailing arms.   12 - Semi-trailer according to any one of the claims   1 to 11, characterized in that the movement of the thrust rods (8) relative to the body (1) of the semi-trailer   is controlled by a pneumatic suspension means (3) available   dried between a distal end of each push rod and an element of the body.   13 - Semi-trailer according to any one of the res-   dications 1 to 12, characterized in that it comprises one or 14. several axles (11) each having a wheel (14) mounted in   rotation on each end and fixed on inter-   middle of a pair of thrust rods (8).