FR2779388A1 - Safety tow bar with predetermined bending point - Google Patents

Abstract

The tow bar (4), joined to a trailer (2) with a coupling (6), is equipped with a predetermined bending point (16). Two V-shaped cuts (18) across the bar (4), covered with a rubber sleeve (14), cause the bar (4) to fold in case of an accident. The coupling (6) is not opened by the impact and the tow bar (4) cannot be pushed into the rear of the car. There are also versions with a bending area (16) made of a softer material (24) or a bending area (16) created by the insertion of hinges (26) available.

Description

The present invention relates to a safety coupling bar, in

  particularly for trailers and the like having one or two axles

  and of the type which comprises at least one loading platform

  carried by wheels, which, via a drawbar link consisting of a straight tubular drawbar provided with a coupling mechanism

  range, can be coupled to a towing vehicle.

  Drawbars are known as V-shaped or straight drawbars, one end of which is attached to the trailer frame and the other end of which includes standard coupling for coupling to a towing hook standard on a

towing vehicle.

  In the event of a collision, it is very important to prevent the drawbar system on the trailer from entering the towing vehicle like a lance, with consequent possibilities of

personal injuries.

  In the event of a collision, the V-shaped drawbar plays a safety role in that the impact forces resulting from the collision are divided between the two bars, the free ends of which are mutually connected immediately in front the coupling mechanism, the consequence being that the collision force first of all causes a deformation of the drawbar system and the chassis before the

  drawbar system pierces the rear end of the vehicle

  masking. This deformation will considerably remove the influence of the force resulting from the collision, so that, in most cases, said

spear effect is avoided.

  To further counteract the spear effect, by the document DK-

  156944 B, a V-shaped drawbar arrangement is known for a single-axle or double-axle trailer, in which deformations are provided on the half of the V-shaped drawbar which leads to the trailer coupling to control deformation which

  occurs during the collision. However, said deformations do not include

  take no separate weakening from the drawbar shaped

  V, but simply guarantee folding in this area when the colli-

sion occurs.

  However, with straight drawbars, there is no known system at present to counteract said lance effect, and trailers having such drawbars thus constitute a

  considerable risk for users.

  Thanks to the invention, one obtains the possibility of counteracting the lance effect occurring during a collision with trailers of the type comprising a straight tubular drawbar, the drawbar, in an area between the mechanism. coupling and the trailer, presenting a collision zone in the form of a weakening of the resistance to

  bending of the drawbar, around which the drawbar is deformed

  when the towing vehicle is involved in a collision

  frontal or a collision from the rear.

  This ensures that the drawbar folds (laterally or downward) before coupling the trailer or the towing hook

  breaks and the drawbar eventually pierces the rear end

tow vehicle.

  The weakening of the bending strength of the drawbar

  may advantageously include cutouts in the tubular material

  drawbar area in one or more locations chosen on the

drawbar.

  With the cutouts, a certain weakening of the resistance of the tube is obtained, which guarantees that, in the event of a collision, the drawbar will be deformed precisely in the area of the cutouts, so that, under the force of the collision, the drawbar is bent outward, which will dampen the impact forces resulting from the collision and, in all cases, will counteract

  the spear effect. It should be noted that the collision zone obtained by the weakening

  The flexural rigidity of the drawbar is possible without this having any significant effect on the nominal capacity of

loading the trailer.

  Regarding the control of the folding of the drawbar in a desired direction in the event of a collision, the cuts can be

  advantageously configured as two elongated cross-cuts

  health extending in parallel, the central axes of which form a

  angle with the central axis of the drawbar.

  In a second preferred embodiment of the safety coupling bar according to the invention, the weakening of the flexural strength of

  the drawbar may consist of at least a part of weakening

  inserted in an area between the coupling mechanism and the

  morque. The advantage in this case is that the establishment of the

  the drawbar does not mean that the drawbar

  telage as a whole must be subjected to work operations, and

  that weakened parts can be produced having characteristics

  resistance ticks specially adapted in accordance with the requirements of the local authorities, without this having any influence on the production of the remaining parts of the trailer. Furthermore, this embodiment allows the manufacturer greater freedom regarding the choice of material thickness, etc. for the tube which is used for the manufacture of the parts.

remaining from the drawbar.

  In another embodiment of the safety coupling bar according to

  the invention, the weakening of the bending strength of the bar

  telage consists of at least one articulated connection arranged in a

  area between the coupling mechanism and the trailer, said articulated link

  abutment comprising cover parts which are fixed by a locking mechanism, the breaking force of which being less than a predetermined force, so that the locking mechanism breaks in the event of a frontal or rear collision, and the bar hitch is folded in the same manner as previously described and the lance effect is avoided. The locking mechanism can be constituted, for example, by a keyed pin or the like through holes in the cover pieces and which is sheared during the collision. The advantage in

  this case is that a minor collision does not result in the need for repair.

  major trailer, but simply replacing the bro-

che keyed.

  However, the spear effect can also be avoided by

  safety drawbar of the type described, in which the force of rup-

  Axial ture of the drawbar is weakened by a tubular piece

  centered on the drawbar, said concentric tubular part being fixed in cover pieces of the tubular part and the drawbar by locking mechanisms having a breaking force which is less than a predetermined force, so that the locking mechanism breaks in the event of a frontal or rear collision. We

  thus obtains a reduction in the length of the drawbar, corresponding to

  according to the effective length of the concentric tubular part, thanks

  how the spear effect is avoided.

  In another advantageous embodiment of the safety coupling bar according to the invention, the safety bar is movable, mounted

  fixedly in the points of attachment to the trailer by mechanical

  Locking meshes having a breaking force which is less than a predetermined force, so that the locking mechanism breaks in the event of a frontal or rear collision. In the event of a collision, it is thus obtained that, by breaking the locking mechanisms, the trailer will be moved along the longitudinal axis of the safety hitch bar towards the towing vehicle, possibly up to that the front end of the trailer collides with the end

  rear of the towing vehicle, thanks to which the lance effect is

annoyed.

  However, practical tests have shown that in the case of col-

  violent lisions, the weakening of the drawbar in the collision zone can result in the breaking of the most

  front of the drawbar with the coupling part and thus also

  the cable which is placed on the coupling part in accordance with

  normal safety rules for a guarantee against loss of re-

  which, by known fixing means, is connected to the mechanism

  towing vehicle hitch.

  In order to avoid the loss of trailers of the type described in the

  If their drawbar breaks, the drawbar according to the pre-

  sente invention may be provided with a cable connection which is drawn in the

  cavity of the drawbar, one end of the cable being fixed to the re-

  behind the collision zone and the other end of the cable being provided with means of attachment to the towing vehicle and extending to

  through the drawbar and a portion of the coupling portion.

  This provides security against the loss of heavy trailers.

  set of tubular drawbars in the event that the drawbar is broken in the collision area, in that the safety cable is attached to the trailer behind the area in which a possible breakage of the drawbar will occur as a result of the weakening of rigidity

  of the drawbar in the collision area.

  To protect the drawbar cavity from the ingress of foreign matter, including water, and to eliminate the dangerous effects of sharp edges in cutouts and to conceal

  the visual impression of a weakened drawbar in the collision area

  the drawbar can be fitted with a tightly fitting sleeve

flexible material tee.

  The figures in the accompanying drawing will make it clear how

The invention can be realized.

  Figure 1 is a perspective view of a trailer provided

  a drawbar, the drawbar being provided with a coupling zone

lision according to the invention.

  Figure 2 is a detailed side view of the collision area

  established as cutouts in the drawbar.

  Figure 3 is a detailed side view of the collision area

in the uncovered condition.

  Figure 4 is a view similar to Figure 3, but in the case

  o the drawbar is deformed in the collision area.

  Figure 5 is a detail view partially in side section

  of a second embodiment of the collision zone according to the invention.

  Figure 6 is a detail side view of a third embodiment

  tion of the collision zone according to the invention.

  Figure 7 is similar to Figure 6, but with the colli-

distorted sion.

  Figure 8 is a plan view of a fourth exemplary embodiment

  sation of the safety coupling bar according to the invention.

  Figure 9 is a perspective view of a fifth embodiment

  of the drawbar according to the invention.

  Figure 10 is similar to Figure 8 after a collision.

  FIG. 1 shows a trailer 2 having a drawbar tu-

  right bular 4 according to the invention, the most front end of which is provided with a coupling part 6 coupled to a standard coupling hook 8 on a vehicle not shown. The trailer comprises a platform having a front end 12. As can be seen in FIG. 1, in

  a zone of the drawbar 4 between the coupling part 6 and the end

  before the platform 12, there is a collision zone 16 overlapping

  green by a rubber sleeve 14 o the bending resistance of the drawbar is weakened. Figure 2 is a detail view of the

  collision zone 1 6 covered by the rubber sleeve 14.

  An example showing how the bending strength of the drawbar is weakened is shown in Figure 3, which is a detailed view of the collision area 16 without the rubber sleeve 14. The

  collision zone 16 consists of two elongated cut-outs

  health 18, arranged in opposite directions, in the sides of the bar

  tubular telage. The cuts are still configured so that

  their axes 20 form an angle V with the axis 22 of the drawbar.

  The effect of the collision zone 16 is that, in the case of a collision

  sion, for example in the event that the trailer is struck by a rear

  First, the drawbar 4 is deformed around the cutouts 18, so that the drawbar 4 is thus folded (see Figure 4) and thus the drawbar does not pierce the towing vehicle. By folding the

  drawbar at the time of a collision, part of the driving forces

  collision pact is absorbed, whereby the influence of the vehicle's

towing is reduced.

  As indicated, the drawbar 4 is also provided with a cable connection 5 drawn inside the cavity of the drawbar, in that one end of the cable is fixed to the trailer 2 in one point

  located behind the collision zone 16, and the other end of the cable

  ble is fitted with fixing means 7 to the towing vehicle,

  extending through the drawbar and a portion of the coupling portion

  beach. Security is thus obtained against loss of the trailer in the event that the drawbar breaks in the collision zone 16, in that the safety cable 5 is fixed to the trailer at the rear of this zone ( collision zone) o a possible breakage of the drawbar 4 would occur as a result of the weakening of the stiffness of the bar

hitch.

  In FIG. 5, there is shown a second embodiment of the safety coupling bar 4, o, instead of establishing separate cutouts 18 (see FIG. 3) in the collision zone 16, a part

  intermediate 24 having a tensile strength which is reduced relatively

  hitch to the drawbar 4, whereby in the event of a collision the drawbar will be deformed in the collision zone and thus the lance effect will be avoided. The advantage of establishing the intermediate part is that

  this provides the possibility to choose different resistance characteristics

  mechanical part 24, depending on the requirements of the authorities

your.

  In FIGS. 6 and 7, a third embodiment of the safety coupling bar according to the invention is shown, where the collision zone 16 is configured with an articulated connection 26 on the coupling bar 4, in which case , through a part 28 in front of the pivot axis 30 of the articulation, a pin 32 is inserted into holes 34, 36 in the part 28 and the drawbar 4, respectively. When there is a

  collision, the safety coupling bar 4 rotates around the pivot axis

  30, as shown in FIG. 7, in that, at the time of the collision, the spindle 32 is cut by the shearing effect which occurs from the force of the collision, which results in rotation

  of part 28 relative to the drawbar 4.

  Figure 8 shows a fourth embodiment of the drawbar

  safety according to the invention, the weakening of the mechanical resistance

  that of the drawbar consists of a concentric tubular piece 38 on the drawbar, said concentric tubular piece being fixed on cover pieces 40 of the tubular piece 38 and of the drawbar 4 by locking mechanisms 42 in the form of pins inserted through holes 41 in the drawbar 4 and the concentric tubular part 38. The breaking force of the pins 42 is

  less than a predetermined force, so that the mechanism of ver-

  rusting is broken by a frontal or rear collision. During the collision,

  pins 42 are cut between opposite surfaces of the drawbar

  telage 4 and tubular part 38, whereby the drawbar

  safety is shortened enough to avoid the spear effect.

  In FIG. 9, a fifth embodiment of the safety coupling bar 4 according to the invention is shown. In this case, the drawbar 4 is fixed firmly but movably to the cross member 44 of the vehicle and to the platform 10 by means of mounting lugs 46.

  mounting lugs 46 of the drawbar 4 have through holes

  slopes 48, 50 into which pins 52 are inserted, the characters

  traction properties of said pins 52 being such that the pins can withstand ordinary conditions of use of the trailer, but such that they will be sheared in the event of a frontal collision or

back.

  In FIG. 10, the trailer shown in FIG. 9 is seen at the time of a collision, in the case where the pins 52 have been sheared (not shown), and the platform 10 and, thus, the end la forward 12 of the trailer were moved forward toward the rear end 54

  of the towing vehicle. During the collision, the part of the bar

  telage 4 extending in front of the foremost end 12 of the trailer is

  thus become shorter, while, at the same time, the coupling 6 res-

  was in place on the towing hook 8 and that the lance effect was thus avoided.

  Thanks to the invention, it is thus obvious that the establishment of zo-

  nes of collision on drawbars according to the invention can comprise

  dre of configurations other than those shown in the

  exemplary embodiments described here. The cutouts 18 can thus present

  other configurations which guarantee that the drawbar 4 of the

  trailer is deformed in the collision area in the event of collisions.

  However, this does not alter the inventive aspect which consists in finding that effectively avoiding the spear effect in the case of a

  collision with trailers fitted with straight tubular drawbars

  This is possible by establishing a collision zone in the form of a

  weakening of the bending stiffness of the straight drawbar,

  depending on whether this is achieved by weakening the bending strength of the drawbar or by reducing the capacity of the bar

  coupling to absorb axial forces, which can be done in mo

  specifying the attachment between the drawbar and the trailer or by modifying

the drawbar itself.

Claims (10)

  1. Safety coupling bar (4), in particular for trailers   ques (2) and the like having one or two axles and of the type which comprises at least one loading platform (10) supported by wheels, which, via a drawbar link consisting of a drawbar straight tubular (4) provided with a coupling mechanism (6), can be coupled to a towing vehicle, characterized in that, in the area between the coupling mechanism (6) and the trailer (2), the bar hitch (4) has a collision zone (16) in the form of a weakening of the bending resistance of the drawbar, around which the drawbar (4) is deformed   in the event of a frontal collision or a rear collision.   2. Safety coupling bar according to claim 1, characterized in that the weakening of the flexural strength of the coupling bar (4) is obtained by providing cutouts (18) in the tubular material of the drawbar in one or more locations   chosen on the drawbar (4).   3. Safety coupling bar according to claim 1 or 2, characterized in that the cutouts (18) are configured as two   elongated through cutouts extending in parallel, the axes center   traux (20) of which form an angle V with the central axis (22) of the drawbar.   4. Safety coupling bar according to claim 1, characterized in that the weakening of the flexural strength of the coupling bar comprises at least one weakening part inserted.   in an area between the coupling mechanism (6) and the trailer (2).   5. Safety coupling bar according to claim 1, characterized in that the weakening of the flexural strength of the coupling bar comprises at least one articulated connection arranged in a zone between the coupling mechanism (6) and the trailer (2), said articulated link comprising covering parts which are fixed   by a locking mechanism, the breaking force of which is less   greater than a predetermined force, so that the mechanism of ver-   rusting breaks in the event of a head-on collision or a rear-end collision. 6. Safety coupling bar, in particular for trailers (2) having one or two axles and of the type which comprises at least one loading platform (10) supported by wheels, which, via a link with a bar coupling consisting of a straight tubular coupling bar   (4) provided with a coupling mechanism (6), can be coupled to a vehicle   towing eye, characterized in that the breaking strength of the drawbar for axial forces is reduced by a concentric tubular piece (38) on the drawbar, said concentric tubular piece being fixed in pieces of covering of the tubular part (38) and of the drawbar (4) by locking mechanisms (42), the breaking strength of which is less than a predetermined force, so that the locking mechanism is broken in in the event of a head-on collision or from a rear collision.   7. Safety coupling bar, in particular for trailers (2) having one or two axles and of the type which comprises at least one loading platform (10) supported by wheels, which, via a link with a bar coupling consisting of a straight tubular coupling bar   (4) provided with a coupling mechanism (6), can be coupled to a vehicle   towing hitch, characterized in that the drawbar is fixed firmly but movably to the trailer by fixing lugs (46) by   locking mechanisms (48, 50, 52), the breaking strength of the   which is less than a predetermined force, so that the locking mechanism (52) is broken in the event of a frontal collision or rear collision.   8. Safety coupling bar according to claim 6 or 7, characterized in that the locking mechanism consists of a pin (42, 52) inserted through holes (41, 48, 50) in the parts of cover (40) or the fixing lugs (46), and which is sheared   in the event of a frontal collision or a rear collision.   9. Safety coupling bar according to any one of the res-   dications 1 to 8, characterized in that the drawbar comprises a cable connection (5) drawn inside the cavity in the drawbar and a portion of the coupling part (6), in that that one end of the cable is fixed to the trailer (2) at a point behind the collision zone (16) and the other end of the cable is provided with means (7) for fixing to the towing vehicle.   10. Safety coupling bar according to any one of the re-   vendications 1 to 9, characterized in that the drawbar (4) is provided with a sleeve   (14) tightly matched with flexible material in the collision zone (16).