Chair fastening device

• US 5,297,851 A
• Filed: 12/05/1991
• Issued: 03/29/1994
• Est. Priority Date: 12/05/1991
• Status: Expired due to Term

• Current Assignee: Knoll Incorporated (Millerknoll Incorporated)
• Original Assignee: Westinghouse Electric Corporation (Paramount Global (f/k/a ViacomCBS Inc.))
• Inventors: Van Hekken, Hendrik R.
• Primary Examiner(s): Dorner, Kenneth J.
• Assistant Examiner(s): Nelson, Jr., Milton
• Application Number:
  US07/802,591
• Time in Patent Office: 845 Days
• Field of Search: 297/DIG. 2, 297/457, 297/454, 297/444, 297/443, 297/440, 297/419, 297/420, 297/455, 297/456, 297/452, 411/172-175, 411/179, 411/180, 411/183, 411/177
• US Class Current: 297/452.14
• CPC Class Codes: A47C 3/00 Chairs characterised by structural features; Chairs or stools with rotatable or vertically-adjustable seats A47C1/00, A47C4/00 take precedence
• CPC Class Codes: F16B 33/002 Means for preventing rotation of screw-threaded elements F16B39/00 takes precedence
• CPC Class Codes: F16B 37/065 by deforming the material of the nut
• CPC Class Codes: Y10S 297/02 Molded

Abstract

A chair fastening device for securing a metal bracket to a seat pan of a chair thereby enabling arms, legs or pedestal bases with or without control mechanisms to be attached to the chair. The fastening device comprises a slab base weld nut which includes a slab base head that is captured and retained by parallel raised ribs formed in the plastic of the seat pan, thereby preventing rotation of the slab base weld nut, and an elongated barrel which is inserted through angled holes in the plastic seat pan and peened over in order to form a rivet connection with the underside of the plastic seat pan. The elongated barrel of the slab base weld nut is counterbored and further includes internal threads adapted to receive a screw or bolt for use in securing a metal bracket to the plastic seat pan without inducing stress fractures in the plastic, thus creating a strong, secure attachment for chair arms, legs or pedestal bases.

Claims

1. A fastener for securing a metal bracket to a seat pan of a chair comprising:

an injection molded plastic seat pan having a front side, a back side and including a plurality of predeterminately spaced oval drafted angle holes and parallel standing rib members formed in the plastic on the front side of said plastic seat pan, said standing rib members surrounding said oval holes; and

a slab base weld nut having a slab base head which is captured and retained by said standing rib members thereby preventing rotation of said slab base nut and an elongated barrel having internal threads and extending through at least one of said oval holes and being peened over to form a rivet connection with the back side of said plastic seat pan.

2. A fastener according to claim 1 further including a metal bracket and at least one threaded bolt, said metal bracket having at least one hole therein, said at least one threaded bolt extending through said at least one hole and being threaded into said internal threads of said barrel of said slab base weld nut to threadedly secure said metal bracket to said plastic seat pan.

3. A fastener according to claim 2 wherein said metal bracket includes means for attaching legs, arms and pedestal bases to said plastic seat pan.

4. A fastener according to claim 3 wherein said means for attaching legs, arms and pedestal bases to said metal bracket includes hollow cylindrical tube means.

5. An improved fastening construction for securing a metal bracket to an injection molded plastic seat pan of a chair, said fastening construction comprising:

a molded plastic seat pan having a front side, a back side and a plurality of predeterminately spaced drafted angle holes therethrough and parallel raised rib members located on said front side of said seat pan and disposed on opposite side edges of said drafted angle holds; and

a slab base nut rivet having an elongated barrel and internal threads extending through at least one of said drafted angle holes, said elongated barrel including two ends, one end of said elongated barrel having a slab base head being disposed between and retrained by said parallel raised rib members thereby preventing rotation of said slab base nut, and a second end of said elongated barrel being peened over to form a rivet connection on said back side of said plastic seat pan.

6. The improved fastening construction according to claim 5 further including a metal bracket and at least one threaded bolt, said metal bracket having at least one hole therein, said at least one threaded bolt extending through said at least one hole and being threaded into said internal threads of said barrel of said slab base nut rivet to threadedly secure said metal bracket to said molded plastic seat pan.

7. The improved fastening construction according to claim 6 wherein said metal bracket includes means for attaching legs, arms and pedestal bases to said molded plastic seat pan.

8. The improved fastening construction according to claim 7 wherein said means for attaching legs, arms and pedestal bases to said metal bracket includes hollow cylindrical tube means.