DE3714588C2 - Safety backrest spar made of plastic - Google Patents

Description

The invention relates to a safety backrest spar Plastic for a vehicle seat backrest of two opposing belts, through at least a spacer are connected to each other.

It is known that the backrest spars of vehicles from U and / or to produce box-shaped profiles, where as Material steel or reinforced plastic used becomes. This construction is usually sufficient for that the person sitting when getting in while driving or Accelerate adequately. This is normal case desirable relentless support of the body but shows very unfavorable effects in rear-end collisions kungen, because then the person is short on full Impact energy is loaded, which is easily injured can lead. Added to this is stiff art fabric profiles, the risk of splinter breakage Exceeding the breaking strength, which is too uncomfortable Injury.

The object of the invention is a backrest beam one Vehicle backrest made of reinforced or unreinforced To find plastic, which is a normal use has sufficient rigidity and which in excess load case - for example in the event of a crash - without externally accessible danger spots through the plastic yields. The energy that occurs during deceleration should be steadily degraded over a longer path will. A possible springback of the backrest beam in the form a so-called whip effect is largely too prevent.

The object is achieved by the Features specified in claim 1 solved.

Further embodiments are in the subclaims specified.

The construction according to the invention prevents changes that when the backrest beam is overloaded an outside horizontal splinter breakage can occur in the plastic, because the destructible connections by notching small have smooth fracture surfaces, and inside the spar lie. At the same time, by extending the bend way the momentary burden for the human being reduced.  

Through a U-shaped bend in the longitudinal web in the loading the neutral bending plane arise after the Ener casting conversion due to the rupture of the destructible ver Binding two separate parts that lose energy slide past each other. This will make the whip effect reduced. There may be further obstacles to the Sliding surface, for example in the form of standing upright connecting parts or other edges Brake the suspension strongly.

But slanted simple or crossed are also conceivable Crosspieces transverse to the longitudinal extension of the belts, which in the middle area has a predetermined breaking point. The ge Broken ends can be shaped so that they are a Allow sliding in one direction while in the act in a different direction than barbs. Finally are Several predetermined breaking points per web are also conceivable, whereby the broken parts, for example, the shape of Have discs which, depending on the direction of travel, have a rolling or Locking effect between the two halves of the broken one Effect Lehnenholms.

Finally, the space formed by the Lehnholm can still filled with a foam (in situ), whereby the damping is increased.

Examples of the invention are shown in drawings and are described in more detail below. Show it:

Fig. 1 Holm backrest with longitudinal and diagonal web,

Fig. 2 backrest Holm with parallel webs,

Fig. 3 backrest bar with X-webs.

In Fig. 1, a backrest beam 1 is shown, which consists of an upper and a lower belt 2 , which are connected to each other by a web 3 , which has an inwardly drawn bend 4 in a U-shape in the central region. A foot 6 is arranged between the two legs 5 and contains alternating openings 7 and destructible connections 8 in the longitudinal direction. Furthermore, two parallel (possibly zigzag) diagonal webs 9 are present between the belts and sit 7 predetermined breaking points 10 at the level of the destructible connections.

In Fig. 2, a backrest beam 11 is drawn, which consists of an upper and lower belt 12 , between which oblique webs 13 are arranged in parallel, which give way elastically under pressure and bending.

In Fig. 3 a backrest spar 21 is shown , which consists of an upper and lower belt 22 , between which curved cross webs 23 are arranged, which reduce the distance between the belts and thus the section modulus when bent.

Claims (7)

1. Safety backrest spar made of plastic for a vehicle seat backrest, consisting of two opposing belts which are connected to one another by at least one spacer, characterized in that the spacers ( 3 , 9 , 13 , 23 ) are arranged in the region of the neutral bending plane, Destructible connec tion points ( 8 , 10 ), the yield or break when a predetermined mechanical load and the resulting parallel shear forces acting in the neutral bending plane. 2. Safety backrest bar according to claim 1, characterized in that a longitudinal web as a spacer ( 3 ) in the central region has a transverse to the connecting plane of the straps ( 2 ) bend ( 4 ), in particular in a U-shape, along the reverse line consists of individual destructible connections ( 8 ). 3. Safety backrest bar according to claim 2, characterized in that the destructible connections ( 8 ) have projections as obstacles against sudden sliding back. 4. Safety backrest bar according to claims 1-3, characterized in that transversely to the longitudinal direction of the straps ( 2 ) obliquely or perpendicularly arranged webs ( 9 ) are arranged as spacers, the at least in the central region between the straps ( 2 ) continuously with predetermined breaking points ( 10 ) are provided. 5. Safety backrest beam according to claim 1-4, characterized in that the predetermined breaking points ( 10 ) have sliding surfaces created by breakage. 6. Safety backrest bar according to claims 1-5, characterized in that the predetermined breaking points ( 10 ) have spring-backed projections resulting from breakage. 7. Safety backrest bar according to claims 1-6, characterized in that the cavities between the belts ( 2 , 12 , 22 ) are at least partially filled with foam.