Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
  • F16F7/00—Vibration-dampers; Shock-absorbers
  • F16F7/12—Vibration-dampers; Shock-absorbers using plastic deformation of members
  • F16F7/128—Vibration-dampers; Shock-absorbers using plastic deformation of members characterised by the members, e.g. a flat strap, yielding through stretching, pulling apart
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
  • B60R22/00—Safety belts or body harnesses in vehicles
  • B60R22/34—Belt retractors, e.g. reels
  • B60R22/341—Belt retractors, e.g. reels comprising energy-absorbing means
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
  • F16F7/00—Vibration-dampers; Shock-absorbers
  • F16F7/12—Vibration-dampers; Shock-absorbers using plastic deformation of members
  • F16F7/123—Deformation involving a bending action, e.g. strap moving through multiple rollers, folding of members

Definitions

• the invention relates to a force limiting device, in particular for seat belts, comprising a mechanism for rewinding the belt strap, fixed at one of its ends to an anchoring wall and which is constituted by a metal blade, the ends are provided with fixing holes.
• the publication BP-A-1170404 describes a device in which a metal blade is shaped in a sinusoidal succession of loops whose summits are joined by riveted plates. In this case, a tensile force exerted at the ends of the device exerts a shearing force on the rivets and a straightening of the metal blade.
• the reaction exerted by the seat belt on the human body is thus maintained at a bearable level.
• the publication FR-A-2168073 describes a force limiting device constituted by superimposed blade portions connected to one another by a fastener and by a fold, among which a blade is integral with reinforcement edges fixed to a structure carrier.
• a force limiting device constituted by superimposed blade portions connected to one another by a fastener and by a fold, among which a blade is integral with reinforcement edges fixed to a structure carrier.
• a force limiting device mounted on a seat belt makes it possible to obtain a predefined lengthening of the seat belt during the acceleration communicated to the occupant of the vehicle following a stop. brutal vehicle following a collision.
• Such force limiters are necessarily linked directly to the seat belt strap, which poses a certain problem of integration on an existing belt model, in particular on a belt model provided with a mechanism for rewinding the strap.
• the invention relates to a force limiting device applied by way of example to an existing seat belt in order to increase the performance of said belt.
• the invention more particularly relates to a force limiter applied between an anchor point of the belt and a winding mechanism, so that the tensile force exerted on said limiter for its plastic deformation, generates a tension stress threshold of a thoracic strap tolerable by the thorax of the belt user.
• the invention also relates to a force limiter whose deformation is made possible in the case where the winding mechanism is located in a housing of reduced space.
• the blade is located in a housing in which a surface cooperates in guiding the movements of the winding mechanism under the action of the tensile force F.
• the guide surface is connected to one end of the metal blade opposite the fixing lugs of said blade.
• the guide surface is constituted by a stamped area of a bodywork element.
• the guide surface has a concavity oriented in the direction of a median longitudinal plane of the vehicle.
• FIG. 1 is a perspective representation of the limiter device.
• FIG. 2 is a distorted representation of the limiter device, as a result of a controlled tear resulting from a tensile force imparted to a fixing end of said device.
• FIG. 3 is a representative diagram of the elongation of the limiter as a function of the applied tensile force.
• FIG. 4 schematically shows an example of application of the limiter device to a seat belt.
• FIG. 5 shows the force limiter carrying a winding mechanism and located in a housing of the middle leg.
• FIG. 6 shows the force limiter in situation in a housing of the middle leg after deformation of said force limiter and movement of the strap winder.
• retractor will be used to define a retractor 2 for a strap 3 of a seat belt 4 which comprises an additional means for blocking said strap 3 at the outlet of said retractor 2.
• the limiting device shown in Figures 1 and 2 is constituted by a portion of metal blade 10 2 mm thick on which the ends folded at right angles materialize fixing lugs 12, 12 'provided with receiving holes 13, 13' d 'fasteners to an anchor wall 15, shown in Figure 4, and to a support plate 48 of a winding mechanism 2 of the strap 3 of seat belt 4.
• One end of the blade 10 opposite the fixing lugs 12 and 12 ' is shaped as a guide surface 17 for the movements of the winding mechanism 2 during the deformation of the force limiter under the action of a tensile force F.
• Two parallel grooves 11, 11 ′ for controlling the tear of the blade 10 which open into holes 16, 16 ′ extend along said blade from priming notches 14, respectively constituted by two symmetrical localized notches at the junction of the fixing lugs 12, 12 '.
• Belt 4 conventionally has:
• a thoracic strap 41 which extends diagonally in service in front of the occupant of the seat 5 from an upper lateral anchor 43 situated above the occupant's shoulder towards a first lower median anchor 44.
• a pelvis strap 42 which extends between said first lower median anchor 44 and a second lower lateral anchor 45.
• a sliding connector means 46 which forms the transition between said straps 41, 42, intended to be connected to a locking box 47 associated with the first lower middle anchor 44.
• the winding mechanism 2 of the strap 3 has a support plate 48 connected to a second lower lateral anchoring 49 via the force limiting device.
• the fixing lugs 12 ′ are intended to be rigidly connected to the anchoring wall 15, such as a side flap reinforcement of a motor vehicle.
• the mounting lug 12 is intended to be connected to the support plate 48 of the winding mechanism 2 of the strap 3 of a seat belt 4 associated with a seat 5 of the vehicle.
• the blade 10 tears along the grooves 11, 11 'under the action of a tensile force F, substantially constant, communicated to the fixing lug
• the distance made between the priming notches 14 and the holes 16, 16 ′ as well as the depth of the grooves 11, 11 ′ defines the value of the energy absorbed and therefore the limit value of the force applied by the strap 3 seat belt 4 on the occupant, during the tearing of the device, which is limited by the holes 16, 16 '.
• section AB represents the initial loading of the force limiter up to the reference force FI (at zero displacement).
• the start of the notch tear phase 14 is represented by point B.
• the tear of the blade 10 with spacing of the parts 12, 12 * at constant force is illustrated by the plate BC of the diagram.
• the section CD represents the final behavior law of the blade 10 when the tears reach the holes 16, 16 ′.
• the winding mechanism 2 of the strap 3 is generally located in a housing 20 made in a bodywork element 30 such as a local reinforcement of the bodywork or on a wall thereof, or a center leg as shown in Figures 5 and 6.
• the example described in FIG. 5 represents the force limiter located in a housing 20 produced at the base of the center leg 30.
• the guide surface 17 of the movements of the reel 2 has a concavity 21 which is oriented towards a median longitudinal plane of the vehicle, which makes it possible to create an extraction ramp 22 directing the reel 2 out of its housing 20 during the deformation of the force limiter, as shown in FIG. 6.
• FIG. 5 and 6 represent the guide surface 17 consisting of a stamped area 23 produced in the center leg, the blade 10 is then limited by the holes 16 and 16 ′ and therefore no longer carries said guide surface 17.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Automotive Seat Belt Assembly (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

ID=9470450

Family Applications (1)

Country Status (4)

Cited By (1)

Families Citing this family (2)

Citations (3)

• 1994
  • 1994-12-30 FR FR9415916A patent/FR2728848A1/fr active Granted
• 1995
  • 1995-12-21 WO PCT/FR1995/001707 patent/WO1996020853A1/fr not_active Application Discontinuation
  • 1995-12-21 EP EP95943254A patent/EP0800466A1/fr not_active Withdrawn
  • 1995-12-21 BR BR9510226A patent/BR9510226A/pt not_active Application Discontinuation

Patent Citations (3)

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