# US 5,700,058 A · Retention for vehicle seat and method of assembly > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,700,058 A - Document ID: US5700058A - Status: Granted - Kind: A - Application number: 08/665,742 - Filed: 1996-06-18 - Granted: 1997-12-23 - Earliest claimed: 1996-06-18 - Assignees: Lear Corporation - Inventors: Ravichandran Balagurumurthy; Jon W. Kinsey - Web page: https://patentgrep.com/patent/US5700058A ## CPC - B60N 2/20: the back-rest being tiltable, e.g. to permit easy access (B60N2/04, B60N2/22 {, B60N2/3002} take precedence) - B60N 2/015: Attaching seats directly to vehicle chassis - B60N 2/42709: {involving residual deformation or fracture of the structure} - B60N 2205/35: Seat, bench or back-rests being split laterally in two or more parts - B60N: SEATS SPECIALLY ADAPTED FOR VEHICLES; VEHICLE PASSENGER ACCOMMODATION NOT OTHERWISE PROVIDED FOR ## Abstract A folding backrest for a passenger seat assembly in a motor vehicle comprises a backrest frame having a first end and a second end. First and second hinges pivotally support the respective first and second ends of the backrest frame about an imaginary horizontal folding axis for movement between a use position and a folded position. A pivot beating is formed in an tab extending from the first end of the backrest frame. A self-locking plastic bushing is positioned in the pivot beating. The pivot bearing and bushing together form a keyway having a pair of diametrically opposing notches. A floor bracket made of mirror-image right and left half sections retain a hinge pin in a perpendicularly extending fashion by sandwiching therebetween a central flange of the hinge pin. The hinge pin includes a keyed tip which is aligned and registerable with the keyway when the backrest frame is in the folded position to permit axial sliding connection between the pivot bearing and the hinge pin during the assembly process. The keyed tip and the keyway are rotated out of registry with one another when the backrest frame is in the use position to prevent disassembly during high impact forces. ## Claims ### Claim 1 A folding backrest for a passenger seat assembly in a motor vehicle, said assembly comprising: a backrest frame having a first end and a second end; a first hinge operatively associated with said first end of said backrest frame and a second hinge operatively associated with said second end of said backrest frame, said first and second hinges pivotally supporting said backrest frame about an imaginary horizontal folding axis for movement between a use position and a folded position; said first hinge including a pivot beating centered along said folding axis and a hinge pin operatively pivotally disposed in said pivot bearing; said hinge pin including a keyed tip and said pivot bearing including a keyway aligned and registerable with said keyed tip when said backrest frame is adjacent said folded position to permit axial sliding connection therebetween during the assembly process and whereby said keyed tip and said keyway are rotated out of registry with one another when said backrest frame is in said use position to prevent disassembly therebetween. ### Claim 2 (depends on 1) An assembly as set forth in claim 1 wherein said keyed tip includes a pair of diametrically opposed wings, and wherein said pivot bearing has a generally circular periphery, said keyway including a pair of diametrically opposed notches extending from said periphery. ### Claim 3 (depends on 1) An assembly as set forth in claim 1 wherein said first hinge includes a floor bracket having a base portion and a center portion, said hinge pin extending perpendicularly from said center portion. ### Claim 4 (depends on 3) An assembly as set forth in claim 3 wherein said hinge pin includes a lug and said center portion of said floor bracket includes a receptacle for non-rotatably receiving said lug. ### Claim 5 (depends on 1) An assembly as set forth in claim 1 wherein said pivot bearing is disposed in said first end of said backrest frame. ### Claim 6 (depends on 5) An assembly as set forth in claim 5 wherein said first end of said backrest frame includes a tab, said pivot bearing being disposed in said tab. ### Claim 7 (depends on 6) An assembly as set forth in claim 6 wherein said first hinge includes a bushing interposed between said tab and said hinge pin. ### Claim 8 (depends on 7) An assembly as set forth in claim 7 herein said bushing includes at least one self-locking tang for engaging said tab. ### Claim 9 (depends on 1) An assembly as set forth in claim 1 wherein said floor bracket includes a right half section and a left half section fixedly attached to said right half section, said hinge pin including a central flange trapped between said right and left half sections. ### Claim 10 (depends on 1) An assembly as set forth in claim 1 wherein said first hinge includes a bushing interposed between said first end of said backrest frame and said hinge pin. ### Claim 11 A folding backrest for a passenger seat assembly in a motor vehicle, said assembly comprising: a backrest frame having a first end and a second end; a first hinge operatively associated with said first end of said backrest frame and a second hinge operatively associated with said second end of said backrest frame, said first and second hinges pivotally supporting said backrest frame about an imaginary horizontal folding axis for movement between a use position and a folded position; said first end of said backrest frame including a pivot beating centered along said folding axis; said first hinge including a floor bracket having a base portion and a center portion; a hinge pin extending perpendicularly from said center portion and operatively pivotally disposed in said pivot bearing; a keyed tip extending from one of said first end of said backrest frame and said floor bracket; and a keyway disposed in the other of said first end of said backrest frame and said floor bracket, said keyway aligned and registerable with said keyed tip when said backrest frame is adjacent said folded position to permit axial sliding connection therebetween during the assembly process and whereby said keyed tip and said keyway are rotated out of registry with one another when said backrest frame is in said use position to prevent disassembly therebetween. ### Claim 12 (depends on 11) An assembly as set forth in claim 11 wherein said keyed tip extends from said floor bracket and said keyway is disposed in said first end of said backrest frame. ### Claim 13 (depends on 12) An assembly as set forth in claim 12 wherein said keyed tip is disposed on said hinge pin and said keyway is disposed in said pivot bearing. ### Claim 14 (depends on 13) An assembly as set forth in claim 13 wherein said pivot bearing has a generally circular periphery, said keyed tip including a pair of diametrically opposed wings and said keyway including a pair of diametrically opposed notches extending from said periphery. ### Claim 15 A method for installing a folding backrest portion of a passenger seat assembly in a motor vehicle, said method comprising the steps of: providing a backrest frame having a first end and a second end; forming a pivot bearing in the first end of the backrest frame; forming a keyway in the pivot bearing; pivotally connecting a second hinge to the second end of the backrest frame; fastening a perpendicularly extending hinge pin to a floor bracket; forming a keyed tip having a shape complimentary to the keyway of the pivot bearing on the hinge pin; attaching the floor bracket to the floor in the passenger compartment of a motor vehicle; folding the backrest frame to a generally horizontal position to align the keyed tip of the hinge pin with the keyway of the pivot bearing, and then axially sliding the hinge pin into the pivot bearing; and attaching the second hinge to the floor in the passenger compartment. ### Claim 16 (depends on 15) A method as set forth in claim 15 further including the step of trapping a central flange of the hinge pin between a right half section and a left half section of the floor bracket. ### Claim 17 (depends on 15) A method as set forth in claim 15 further including the step of mechanically interlocking the hinge pin and the floor bracket for preventing relative rotation therebetween. ### Claim 18 (depends on 15) A method as set forth in claim 15 further including the step of interposing a bushing between the hinge pin and the pivot bearing for dampening vibrations. ### Claim 19 (depends on 15) A method as set forth in claim 15 wherein said step of forming the keyed tip on the hinge pin is performed after said step of fastening the hinge pin to the floor bracket.