Plastics chair shell
Patent 4418958 Issued on December 6, 1983. Estimated Expiration Date: 
January 21, 2001. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
January 21, 2001. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesInventorApplicationNo. 06/226888 filed on 01/21/1981US Classes:297/452.15Including means to provide or enhance resiliency (e.g., slits, grooves, etc.)ExaminersPrimary: Zugel, Francis K.Attorney, Agent or FirmInternational ClassesA47C 7/46 (20060101)A47C 3/12 (20060101) A47C 3/00 (20060101) A47C 7/02 (20060101) Foreign Application Priority Data1980-01-21 GBAbstractA chair shell of resilient material such as polypropylene comprises a back support 12 and a seat portion 14. The natural deformability of the back support 12 is modified by slits 22, 24 and holes 32, 34, 36 so that under pressure from the back of a sitter resting against the back support the support is resiliently deformed into a shape which, in vertical section, includes a convex curve positioned properly to support the sitter's spine in the lumbar region and which is horizontal in convex section. The deformability of seat 14 can be modified by slits 42, 44 and holes 42, 46, 48, 50, 54 to provide softer rear and front zones 44 and 52 to reduce the pressure on the ischial tuberosities and lower thighs of the sitter. The chair shell provides comfortable and orthopaedically desirable support while avoiding the need for thick upholstery. The undeformed state of the chair shell may be designed to allow the chairs to be easily stacked. | |
