AU604372B2 - Improved seat shell construction - Google Patents

Description

I ~CLI'- S F Ref: 40248 FORM COMMONWEALTH OF ALRIA4 7 2 PATENTS ACT 1952 COMPLETE SPECIFICATION

(ORIGINAL)

FOR OFFICE USE: Class mt. Class Application Number: Lodged: PI4856 13 October 1987 Accepted: Published: Priority: Related Art: Name and Address of Applicant: $t Actual Inventor: Address for Service: Kelrit Pty Ltd trading as Spray Coatings Shed 12 Clyde Street Broadmeadow New South Wales 2292

AUSTRALIA

Phillip John Brogan Spruson Ferguson, Patent Attorneys, Level 33 St Martins Tower, 31 Market Street, Sydney, New South Wales, 2000, Australia .4

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Complete Specification for the invention entitled: Improved Seat Shell Construction The following statement is a full description of this invention, including the best method of performing it Pnown to me/us 2 'L 7T ax i t

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i AN IMPROVED COMPOSITE SEAT-SHELL CONSTRUCTION TECHNICAL FIELD The present Invention relates to Improved composite seat-shell constructions, 5 BACKGROUND ART Conventional seating shells, that Is, the seat cushion support structure, have to date used formed plywood, pressed s,,e°l or a moulded solid plastic to produce a shell of sufficient strength and suitable shape for use as a transport seat, The seat-shell is necessarily strong enough to withstand tensile and compressive forces resulting from a person sitting thereon, said forces being due to bending induced by the person between the backrest and the seat portions, or proximate the location of the mounting plate of a S pedestal support or leg supporting the seat-shell.

Jl5" However, previous seat-shell designs fiave not fully accounted for differences in tensile and compressive forces encountered between different areas of the shell, That is, the dimensions and hence the strength characteristics of the material are chosen with respcGL'c-to the maximum forces encountered, and the dimensions of the material, by its nature, often do not vary between the different areas of the seat-shell. For example, a plywood shell may be designed to withstand the maximum bending moments encountered in specific zones of the shell, and the complete shell will be produced from the plywood having the necessary strength to withstand these maximum forces, It is the object of the present invention to overcome or substantially ameliorate the abovementioned problems.

DISCLOSURE OF THE INVENTION In one broad form the present invention comprises a seat-shell having a construction comprising first and second outer skii s. iach of said skins :i h 1.-n 11

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.b7 SAR/1384b 2 r rn,~y having a predetermined thickness; and at least one layer of a formed sheet having regularly spaced and generally parallel ribs prtec .t transverse to the plane ter--of, and which Is/are positioned between said outer skins to form a composite bonded sandwich constrution; said construction being formed into a predetermined shape and which has various numbers of said layers at different predetermined zones of said shape, In a preferred form of the present invention, the sandwich 4j construction of said seat-shell further comprises high density inserts at predetermined positions between, and being secured to said outer skins, The high density inserts are preferably positioned to provide an attachment means for mounting brackets to support said seat-shell, and to enable ancillary fixtures and trimmings to be mounted thereon, i In another preferred form of the present invention the ribs of said planar insert comprise a regular profile defining a plurality of alternate 157' and parallel upper and lower wall sections, joined by a plurality of transverse wall sections, and wherein said upper and lower wall sections abut said first or said second outer skins or upper or lower wall sections of adjacent planar insert, and are bonded thereto.

BRIEF DESCRIPTION OF THE INVENTION A preferred form of the present invention will now be described by way of example with reference to the accompanying drawings, wherein: Fig. 1 is a schematic sectional view of a seat ircorporating the seat-shell of the present invention; Fig. 2 is a schematic exploded view of the seat-shell of the present invention, and a support leg, and ancillary equipment to be mounted thereto; Fig. 3 is a schematic perspective part-sectional view of the seat-shell; and Fig. 4 is a schematic cross-sectional view of the seat-shell.

SAR /l34 1 b -3sS 4i.

BEST MODE OF CARRYING OUT THE INVENTION There is depicted in the drawings a seat-shell 10 having a sandwich construction wherein a first outer skin 11, and a second outer skin 12 sandwiches at least one layer of a formed sheet 13 disposed therebetween.

The outer skins are the formed planar sheet are preferably made from Fibre Reinforce Plastic (FRP), The thickness of the outer skins (11 and 12) is predetermined to provide the composite sandwich construction with greater strength where necessary.

The sandwich construction is formed Into the desired shape of a !i seat-shell 10, and in the zones of the she'lI requiring increased tensile i Iand compressive strengths, multiple layers of the formed sheet 13 may be

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ji incorporated, Such zones would include the transition zone between the backrest and seat portions of the shell, and between the support (e,g.

pedestal leg) and the forward and rearward edges of the'seat portions jI' supported thereby, The formed sheet 13 may have a tapered "transverse" jI dimension to allow for a smooth transition between zones having different S numbers of layers.

The formed sheet(s) 13 are bonded to the internal surfaces of the outer skins (11 and 12) or to an adjacent sheet 13 with a bonding "glue" Shaving the characteristics |i of high elongation, high tear strength and fire retardancy.

S' The sandwich construction further comprises high density foam inserts I provided at suitable locations such as the area(s) for mounting the seat-shell onto the supports 17, and the areas where ancillary fixtures 18 are required to be mounted thereto. In this regard, 't is preferable to provide a foam insert around substantially the complete perimeter of the shell, to improve the rigidity of the complete seat-shell structure.

SAR/1384b -4- -_i2 4. The formed sheet 13 Is formed with a FRP material approximately 1.2 mm thick, and has a profile comprising alternate upper and lower outer walls 14 integrally joined to transverse walls 15 each connecting an alternate upper and lower outer wall 14.

The advantages of this type of sandwich construction is that the relative compressive and tensile strengths of different zones of the formed seat-shell may be varied depending on the number of 'a:ers of formed planar inserts are Incorporated, Together with the high density foam inserts, superior strength characteristics may be designed for specific zones of the i| 10 seat-shell, and the composite structure may be lighter, stronger and more durable than known seating shells of this type, id ft i t ti SAR/1384b

Claims (5)

1. 2. The seat-shell as defined in claim 1 wherein each of said formed sheets is formed from a generally rigid planar material, and said ribs project from one surface only of said sheet(s), whereby said sheet(s) has/have a predetermined dimension normal to the plane thereof.
2. 3. The seat-shell of claim 2 wherein said predetermined dimension of a second or further sheet is gradually reduced In a tapering fashion towards a periphery thereof.
3. 4. The seat-shell of any one of claims 1 to 3 wherein said construction further comprises a mounting means for sead seat-shell S' comprising high-density Inserts provided In place of said formed sheets at I predetermined areas of said shape, said inserts being located between and bonded to each of said outer skins. The seat-shell of claim 4 wherein said predetermined areas comprise areas for mounting said seat-shell onto support members, areas for i mounting ancillary fixtures to said seat-shell, and/or areas proximate the i{ perimeter of said seat-shell.
4. 6. The seat-shell of any one of claims 1 to 5 wherein said outer skins and said formed sheets are made from a fibre reinforce plastics material.
5. 7. A seat-shell as hereinbefore described with reference to and as shown in the accompanying drawings. DATED this TWENTY EIGHTH day of AUGUST 1990 BAr Kelrit Pty Ltd Trading As Spray Coatings Patent Attorneys for the Applicant VSPRUSON FERGUSON -FI4 -6- HRF/0413r