Method of manufacturing a backrest structure for a vehicle seat and backrest structure obtained by this method

• US 6,352,311 B1
• Filed: 12/06/1999
• Issued: 03/05/2002
• Est. Priority Date: 12/04/1998
• Status: Expired due to Fees

• Current Assignee: Bertrand Faure Equipements SA
• Original Assignee: Bertrand Faure Equipements SA
• Inventors: Hayotte, Sébastien
• Primary Examiner(s): Brown, Peter R.
• Application Number:
  US09/455,101
• Time in Patent Office: 820 Days
• Field of Search: 297/452.18, 297/452.2, 294/211, 298/972, 72/58
• US Class Current: 297/452.2
• CPC Class Codes: B60N 2/68 Seat frames
• CPC Class Codes: B60N 2/682 Joining means
• CPC Class Codes: B60N 2205/35 Seat, bench or back-rests being split laterally in two or more parts
• CPC Class Codes: Y10T 29/49622 Vehicular structural member making
• CPC Class Codes: Y10T 29/49805 Shaping by direct application of fluent pressure

Abstract

A backrest structure for a vehicle seat comprises two hydroformed, tubular, horizontal crosspieces and vertical uprights engaged without any clearance in orifices punched into these crosspieces during hydroforming.

Claims

1. A method of manufacturing a backrest structure of a seat for a vehicle, this structure comprising:

a tubular-shaped, rigid, bottom horizontal crosspiece delimiting a certain interior volume and comprising a bottom part and a top part,

a tubular-shaped, rigid, top horizontal crosspiece delimiting a certain interior volume and comprising a bottom part and a top part,

and at least first and second rigid, substantially vertical uprights, each of which extends between bottom and top ends joined respectively to the bottom and top crosspieces,

said method comprising at least one step in which the bottom and top crosspieces are shaped by hydroforming, characterized in that when hydroforming the bottom crosspiece, as the interior volume of this bottom crosspiece is being filled with pressurized liquid, at least first and second pairs of orifices are punched into said bottom crosspiece, the first pair of orifices in the bottom crosspiece comprising two reciprocally matching orifices arranged respectively in the top part and in the bottom part of the bottom crosspiece and having sections matching the bottom end of the first upright, and the second pair of orifices of the bottom crosspiece comprising two reciprocally matching orifices arranged respectively in the top part and in the bottom part of the bottom crosspiece and having sections matching the bottom end of the second upright,

in that when hydroforming the top crosspiece, as the interior volume of this top crosspiece is being filled with pressurized liquid, at least first and second pairs of orifices are punched into said top crosspiece, the first pair of orifices of the top crosspiece comprising two reciprocally matching orifices arranged respectively in the bottom part and in the top part of the top crosspiece and having sections matching the top end of the first upright, and the second pair of orifices of the top crosspiece comprising two reciprocally matching orifices arranged respectively in the bottom part and in the top part of the top crosspiece and having sections matching the top end of the second upright,

and in that the hydroforming step is followed by an assembly step, in which;

the bottom ends of the first and second uprights are engaged without any clearance respectively in the first and second pairs of orifices of the bottom crosspiece,

the top ends of the first and second uprights are engaged without any clearance respectively in the first and second pairs of orifices of the top crosspiece,

and the uprights are definitively joined to the crosspieces in order to prevent the uprights from slipping out, mechanical strength essentially being imparted to the backrest structure by the location of the uprights in the crosspieces without any clearance.

2. A method as claimed in claim 1, wherein the backrest structure has at least two seats side by side, this structure having a third rigid, substantially vertical upright which extends between bottom and top ends joined respectively to the bottom and too crosspieces, the method comprising the following additional steps:

when hydroforming the bottom crosspiece, at least a third pair of orifices is punched into a top part of said bottom crosspiece, the third pair of orifices in the bottom crosspiece comprising two reciprocally matching orifices arranged respectively in the top part and in the bottom part of the bottom crosspiece and having sections matching the bottom end of the third upright,

when hydroforming the top crosspiece, a least a third pair of orifices is punched into a bottom part of said top crosspiece, the third pair of orifices in the top crosspiece comprising two reciprocally matching orifices arranged respectively in the bottom part and in the top part of the top crosspiece and having sections matching the top end of the third upright,

the bottom and top ends of the third upright are engaged without clearance respectively in the third pairs of orifices of the bottom and top crosspieces,

and the third upright is definitively joined to the crosspieces in order to prevent the third upright from slipping out, mechanical strength essentially being imparted to the backrest structure by the location fit of the first, second and third uprights in the crosspieces without any clearance.

3. A method as claimed in claim 1 or claim 2, in which the uprights are definitively joined to the crosspieces by welding.

4. A a method as claimed in claim 1 or claim 2, in which the uprights are definitively joined to the crosspieces by clamping.

5. A structure for a seat backrest of a vehicle produced by a method as claimed in claim 1 or claim 2, made from steel.

6. A structure for a seat backrest of a vehicle produced by a method as claimed in claim 1 or claim 2, made from a material selected from aluminium and aluminium-based alloys.

7. A structure for a seat backrest of a vehicle as claimed in claim 6, in which the bottom and top crosspieces have gutters for fixing a cap covering the backrest, these gutters being cast from the same material with said crosspieces.

8. A structure for a seat backrest of a vehicle as claimed in claim 6, in which the bottom crosspiece forms flanges designed for pivotally mounting the backrest on the vehicle, these flanges being cast in the same material with said bottom crosspiece.

9. A structure for a seat backrest of a vehicle produced by a method as claimed in claim 1 or claim 2, in which the top crosspiece also has at least one additional punched orifice into which an element selected from the following is fixed:

a pin for a headrest,

a riveted fixing insert,

a backrest bolt,

a plate for a backrest bolt,

a mounting for a safety belt reel,

an outlet for a safety belt strap.

10. A structure for a seat backrest of a vehicle produced by a method as claimed in claim 1 or claim 2 having at least one place for a user and the bottom crosspiece has a portion that is flattened on a substantially vertical plane on a level with this seat.