FR2779399A1 - Rear holder net for motor vehicle interior - Google Patents

Abstract

The net consists of a number of woven net cords (V1-7), which are connected to form a mesh. At least a part of the net cords consists of a knitted fabric. The cords are made of threads with differently elasticities. Alternatively, the threads can be differently laid, i.e. have different pitches, so that the net cords have elasticity characteristics, which can be described with an elasticity characteristic curve, which has several tensile stress extrema (maxima and minima), between a non-tensioned position and an extension that causes a breaking stress of the cord.

Description

RETAINING NET FOR FIXING IN THE INTERIOR OF A CAR

SPECIAL

  The invention relates to a retaining net to be fixed inside a private car, composed of a multiplicity of skeins of net connected together to form net meshes, the skeins of the retaining net being manufactured, at

  less in part, in mesh textile.

  These types of retaining nets have been known for a long time. These nets are used in particular in station wagons as a "safety separation" between the driver / passenger area of the passenger compartment of the car and the loading area, and are usually fixed directly behind the back of the rear seats. These nets are mainly intended, in the event of a rear collision or severe braking, to retain objects which would otherwise be thrown into the driver / passenger area from the loading area. In order to also ensure the retention of heavy objects, a retaining net must be designed to absorb relatively large forces, the net having to deform only relatively little in order to guarantee that the passengers seated in the rear are sufficiently protected, in particular at head level. But at the same time, a retaining net must have a certain flexibility or elasticity to absorb the kinetic energy of objects thrown forward and to slow them down in the softest and most harmless way possible. Such restraint systems typically consist of vertical and horizontal tangles of net. Vertical skeins are often made of mesh textile and

  serve primarily to absorb forces or energies.

  At the knots of the net, the horizontal skeins crisscross with the vertical skeins and maintain these

last at a constant distance.

  The task of the invention is to create a retaining net having retaining and energy absorbing properties. This task is solved according to the invention by the fact that the mesh skeins are composed of threads with different tension-elongation behaviors and / or in that these threads have different poses or different thread entries, so that the skein meshed with from these wires have a tensile-elongation behavior which can be described by a characteristic tension-elongation curve which has several extreme values of tensile force between an unelongated state and an elongation leading to the rupture of these

skeins of fillet.

  According to an advantageous embodiment, the skeins of mesh netting are designed so that the characteristic tension-elongation curve has a first elongation zone with an increasing tension force, a following elongation value or a second elongation zone. elongation with a maximum tensile stress, and a third zone with a greater elongation in which the tension stress decreases to a minimum tension stress which is small compared to the maximum tension stress, and finally a fourth zone with an even greater elongation and in which

  the tension force increases again.

  The skeins of net can advantageously be made of a meshed textile material having columns of mesh

  with reinforcing threads inserted in the warp direction.

  The invention is based on the idea of absorbing "in stages",

  that is to say gradually reduce the kinetic energy of an object thrown into the retaining net and to use for this a retaining net which is, at least in part, made up of mesh skeins. The absorption of energy "in stages" means that the mechanical tension force which occurs in the different meshed skeins increases and decreases alternately at the same time as the elongation increases, that is to say that a tension-elongation characteristic curve describing the tension-elongation behavior of the retaining net has several local extreme values. The characteristic tension-elongation curve of the retaining net according to the invention therefore has a "zigzag" shape and has several extreme tension values between a non-elongated state and an elongation resulting in the rupture of the retaining net, this elongation being designated hereinafter by the expression

"elongation at break".

  Such an elongation behavior at break of the retaining net allows the energy to be suppressed or the object to be braked in several braking stages, most of the energy to be absorbed can already be absorbed by an elongation of low importance. When the tension effort reaches a certain local or absolute maximum, the tension effort decreases while the elongation and absorption of energy continue, then the effort increases again. Such a "tension limitation" is especially of interest when transporting animals in the loading space, since in the event of an accident they can thus be retained with a

some care.

  A retaining net of this type is achievable by manufacturing the skeins meshed with columns of mesh having different behaviors of elongation at break. During the elongation of a skein of mesh netting, the respective tension-elongation curves of the different columns of stitches are superimposed. This makes it possible to "construct" in a relevant way a behavior in tension-elongation chosen for the retaining net. It is possible, for example, to make the mesh columns from yarns with different poses or different yarn entries, in order to obtain different characteristic tension-elongation curves. Thus, it is possible to obtain different characteristic tension-elongation curves simply by virtue of a constructive arrangement of the different wires of the mesh assembly, which is designated hereinafter by

  the expression "extension of construction".

  As an alternative or in addition to this, it is also possible to manufacture the mesh columns with wires having different tension-elongation behaviors, the mesh columns in the warp direction being provided with reinforcing wires. Reinforcement threads can be threads

  single or bundles of individual fibers.

  In particular, it is possible to influence the tension-elongation behavior in a relevant manner by using different yarn materials. For example, the threads with which the skeins of mesh mesh are made can be made of different materials, in particular by using polyester, carbon and / or aramid fibers resistant to

  ultraviolet, or using metallic wires.

  Preferably, the retaining net is designed so that its characteristic tension-elongation curve has a first elongation value or a first elongation zone with an absolute maximum of the tension force and a zone following o the elongation is greater and in which the tension force decreases to a local minimum of tension force,

  followed again by an increase in the tension force.

  According to an advantageous embodiment, the skeins of netting made of a meshed textile material can comprise longitudinal skeins, for example vertical, which are connected to each other by transverse skeins, for example horizontal, arranged across longitudinal skeins . The transverse skeins can in particular be

  made up of bundles of coated fibers or monofilaments.

  The invention is explained below in detail using an embodiment in relation to the drawing. There are: Fiaure 1 a schematic view of part of a retaining net according to the invention; Figure 2 an enlarged representation of a mesh of the retaining net of Figure 1, front view; Figure 3 a rear view of the mesh of Figure 2; Figure 4 an enlarged representation of a mesh with the extension of construction; and Figure 5 a tension-elongation diagram of a skein of

mesh net.

  Figure 1 shows a partial area of a retaining net according to the invention. The retaining net consists of vertical skeins Vl-V7 and horizontal skeins H1-H5 arranged transversely to the first. The skeins designated here by the expression "horizontal skeins H1-H7", each consist of two individual skeins 1 and 2 close to each other. In the embodiment shown here, the vertical skeins Vl-V7 and the horizontal skeins H1-H5 cross each other perpendicularly, the vertical skeins Vl-V7 having an average distance x between them and the horizontal skeins Hl-H5 an average distance y . Here, the distances x and y are identical, so that square mesh is obtained 3. If the distances x and y have for example a value of approximately 2.5 cm, one obtains a sufficiently tight mesh so that it can hold even relatively small objects, and sufficiently spaced to allow the driver to have a good visibility towards the rear. The vertical skeins Vl-V7 of the retaining net shown in Figure 1 are made of a meshed textile material. They are arranged to absorb most of the forces that the retaining net must support. At the ends of the vertical skeins Vi, V4 and V7 are placed respectively the eyelets 4, 5, 6, 7, 8 and 9, which make it possible to fix the net in a vehicle. In a station wagon, for example, it is possible to install hooks on the roof rails and on the loading platform or the backrest, the eyelets 4-9 of the retaining net being hung in them. If it is possible to fix the retaining net in addition to the sides of the vehicle, eyelets or other fixing means can be placed

  suitable for horizontal skeins Hl-H5.

  At the points of intersection - only one of which is designated here by the reference 10 - the horizontal skeins Hl-H5 of the retaining net are fixedly connected with the vertical skeins Vl-V7, the latter being held in relation to the

  others at constant distances x.

  As an alternative to the example of embodiment shown, in which only the vertical skeins Vl-V7 are produced in mesh textile material, the horizontal skeins Hl-H5 can also be produced in mesh textile. In addition, the cracks

  may be other than rectangular.

  Figure 2 shows an enlarged representation of the net mesh 3 shown in Figure 1, which is formed by the two vertical skeins V1 and V2 as well as by the two horizontal skeins Hi and H2. The vertical mesh skeins V1 and V2 each consist of four segments of mesh fabric arranged parallel to each other, which are called mesh columns Mi, M2, M3 and M4. Each of the mesh columns here has a zigzag mesh wire 11 in the warp direction, that is to say in the longitudinal direction of the vertical skein V1 or V2, this mesh wire 11 being designated here by the expression "holding wire". The holding wires 11 of the different columns of stitches M1-M4 are. another mesh (see Figure 3) - which is called here "laying wire" - with the vertical skein Vi or V2. Let us indicate that for the vertical skeins V1-V7 or for their columns of meshes M1-M4, other types of mesh connection are possible, of which one does not

  will not speak further in this description.

  Each of the columns of stitches M1-M4 has, in the warp direction, a reinforcing thread 13, 14, 15 or 16 which consists of a multiplicity of individual fibers. The reinforcing threads 13-16 of the vertical skeins V1 and V2 therefore form an integral part of the corresponding mesh columns M1-M4 or of the vertical skeins Vi and V2. These reinforcing fibers 13-16 absorb the major part of the forces which the retaining net must support and can be made of different fiber materials, such as for example polyester, carbon or aramid fibers. The choice of different materials for the reinforcing threads 13-16 makes it possible to obtain, for the corresponding mesh columns M1-M4, different characteristic curves of tension-elongation, which are superimposed on the characteristic curve of tension-elongation which results for the vertical skeins. V1 and V2. As an alternative or in addition to this, it is also possible to influence in a relevant way the characteristic tension-elongation curve of the vertical skeins V1 and V2 by having recourse to different laying of thread or to different entries of thread, which is a

  process well known in the mesh technique.

  Figure 2 also shows that the horizontal skeins Hi and H2 formed by the individual skeins 1 and 2 each consist of a multiplicity of individual fibers which intersect with the mesh network of the vertical skeins Vl and V2 and are therefore connected to the skeins vertical V1 and V2 fixedly. The horizontal skeins Hi and H2 are used primarily to fix or position the vertical skeins V1 and V2. Their individual skeins 1 and 2 made of individual fibers can be glued with a coating. As an alternative to this, it is also possible to use monofilaments for the skeins called individual skeins 1 and 2. The arrangement of the individual skeins 1 and 2 per pair of two closely spaced parallel skeins gives the retaining net, compared to the design with a single individual skein, better transverse stability of the retaining net, and a corresponding appearance. Figure 3 shows a rear view of the mesh 3 shown in Figure 2. We recognize the laying wire 12, which is arranged in a zigzag and forms with the holding son 11 (Figure 2) and the reinforcing son 13- 16 mesh columns

M1-M4.

  Figure 4 shows an enlarged representation of a mesh 3 of the retaining net according to a variant of the invention, in which "the energy absorption in stages" is obtained by the elongation of construction. In this exemplary embodiment, the two outer reinforcing threads 13 and 16 of the vertical meshed skeins V1 and V2 are stretched in the unloaded state, while the inner reinforcing threads 14 and 15 describe a zigzag and therefore have a certain reserve. of wire. When the vertical skeins V1 and V2 are loaded by tension, it is first of all the external reinforcing threads 13 and 16 drawn which absorb the forces and lengthen accordingly. Due to their zigzag arrangement, the reinforcing threads 14 and 15 first absorb only a small part, or even no tensile force. If the tensile forces exerted on the vertical skeins V1 and V2 exceed a certain value, an additional elongation of the vertical skeins V1 and V2 causes the rupture of the stretched outer vertical wires 13 and 16. Due to the additional elongation, the internal zigzag reinforcing threads 14 and 15, which until then were barely loaded, are stretched and absorb most, or even almost all of the tensile forces of the vertical hanks

V1 and V2.

  As an alternative or in addition to the embodiment described in FIGS. 2 and 3, in which the reinforcing wires 13-16 are made of different materials, it is therefore also possible to obtain by construction - by providing an elongation construction - several "energy absorption stages", that is to say by making the different threads of the skeins V1 and V2 be laid differently or have different inputs. The number of energy absorption stages is "constructed" with relevance from the number of reinforcing wires 13-16 provided with different poses. The concrete realizations of such poses are very widespread in the mesh technique and will not be

further developed here.

  FIG. 5 shows a tension-elongation diagram, the tension force c being carried on the ordinate and the elongation E being carried on the abscissa. In the tension-elongation diagram are plotted a characteristic tension-elongation curve 17 of the vertical skeins V1-V7 of the retaining net according to the invention and a characteristic tension-elongation curve of a skein of mesh netting according to the state of the technical. The characteristic curve 18 according to the state of the art has a tension force curve which constantly increases until an elongation S1 and which drops slightly until a

  elongation at break SR in case of additional elongation.

  In contrast to this, the voltage- characteristic curve

  elongation of vertical mesh skeins Vl-V7 of the retaining net according to the invention has a zigzag shape,

  which can be divided into several elongation zones I to IX.

  In the elongation zone I, the characteristic curve tension-

  elongation increases rapidly from a non-elongated state O to a maximum of the tension force MAX1, which is here an absolute maximum. If the elongation continues, there is a slight decrease in the elongation zone II, then a further increase in the tension force a to a value which corresponds approximately to the maximum of the stress force. MAX1 voltage. This variation in the tension force in the elongation zone 2 is for example due to the fact that the vertical mesh skein VI is composed of several single threads or of several individual fibers which shift or begin to break in part. Such relatively small variations in the tension force a can also occur in other areas of elongation of a mesh skein and do not have

  great significance for the invention.

  However, the following larger decreases or increases in the tension force a in the elongation zones III to IV are characteristic for the meshed skeins V1-V7 according to the invention. In the elongation zone III, the tension force a rapidly decreases, from the maximum MAX1, to a local minimum MINi, the value of which corresponds to approximately a quarter of the value of the maximum of the force MAX1 voltage. In the following elongation zone IV, there is a further increase in the tension force up to a local maximum MAX2, the value of which corresponds to approximately half of the absolute maximum of the tension force MAX1. In the elongation zone 5, the tension force decreases to a new local minimum MIN2, to increase again in the elongation zone VI to a local maximum MAX3. In the elongation zone VII, the tensile force decreases to a local minimum MIN3, then increases to a local maximum MAX4 in the elongation zone 8. A further increase in the elongation E until at a DR value results in a drop in the tension force C and a break

  of the meshed skein in the event of tension stress CR-

  Unlike the state of the art, the characteristic tension-elongation curve 17 is characterized by a "large tension peak" which extends over the elongation zones I to III. This peak is due to the rupture of one or more of the reinforcing wires 13-16 and / or to the deformation or rupture of the wires of the mesh assembly which have different wire entries. If for example, as seen in Figures 2 and 3, four reinforcing wires 13-16 are used which are manufactured with different

  materials, we obtain a characteristic curve voltage-

  elongation similar to that shown in Figure 4, the four "peaks" MAX1, MAX2, MAX3 and MAX4 being due to the breakage of the 4 reinforcing wires 13-16 with different tensions or different elongations E. The "big voltage peak" which extends over the elongation zones I to III makes it possible to absorb most of the energy to be absorbed already in the event of deformation or slight elongation of the retaining net. Residual energy is removed by lengthening or breaking the

  other yarns of Vl-V7 mesh skeins.

Claims (8)

  1. Retaining net to be fixed in the passenger compartment of a private car, composed of a multiplicity of skeins of net linked together to form net meshes, the skeins of the retaining net being manufactured, at least in part , in knitted textile material, characterized in that the knitted skeins (Vl-V7) consist of threads (11-16) with different tension-elongation behaviors and / or in that these threads (11-16) have different poses or different yarn entries, so that the skeins (Vi-V7) meshed from these yarns exhibit a tension-elongation behavior which can be described by a characteristic tension-elongation curve (17) which has several extreme values tension force (MAXl-MAX4; MIN1-MIN3) between an unelongated state (0) and an elongation (DR) leading to the rupture of these tangles of fillet (Vl-V7).   2. Retaining net according to claim 1, characterized in that the meshed net skeins (Vi-V7) are designed so that the characteristic tension-elongation curve (17) has a first elongation zone (I) with a increasing tension force, a following elongation value or a second elongation zone (II) with a maximum tension force (MAX1), and a third zone (III) with a greater elongation in which the tension force (a) decreases to a minimum tension force (MINi) which is small compared to the maximum tension force (MAX1), and finally a fourth zone (IV) with an even greater elongation and in   which the tension force (a) increases again.   3. Retaining net according to one of claims 1 or 2,   characterized in that the skeins of net (Vl-V7) made of a meshed textile material have columns of mesh (M1- M4) with reinforcing threads (13-16) inserted in the warp direction. 4. Retaining net according to claim 3, characterized in that the reinforcing wires (13-16) each consist of a bundle of individual fibers.   5. Retaining net according to any one of the claims 1 to 4,   characterized in that the threads (11-16) with which the skeins are made   mesh nets are made of different materials.   6. Retaining net according to any one of the claims 1 to 5,   characterized in that the threads (11-16) with which the meshed skeins are made are made of polyester fibers,   carbon and / or aramid or are made of metal wires.   7. Retaining net according to any one of the claims 1 to 6,   characterized in that the skeins of net (Vl-V7) made of a meshed textile material are longitudinal skeins which are connected to each other by transverse skeins   (H1-HS) arranged across longitudinal skeins.   8. Retaining net according to claim 7, characterized in that the transverse skeins (Hl-H5) consist of   bundles of coated fibers or monofilaments.