Foldable chair frame

• US 6,056,354 A
• Filed: 06/12/1998
• Issued: 05/02/2000
• Est. Priority Date: 06/12/1998
• Status: Expired due to Fees

• Current Assignee: Shin Yeh Enterprise Co., Ltd.
• Original Assignee: Shin YEN Enterprise Company Limited
• Inventors: Tseng, Chuen-Jong
• Primary Examiner(s): Cuomo, Peter M.
• Assistant Examiner(s): Allred, David E.
• Application Number:
  US09/097,132
• Time in Patent Office: 690 Days
• Field of Search: 297/56, 297/55, 297/29, 297/53, 108/120, 108/119
• US Class Current: 297/56
• CPC Class Codes: A47C 4/24 with cross legs

Abstract

A foldable chair frame includes a seat frame formed with an elongated groove which extends from a front end portion to a rear end portion of the seat frame, a first leg frame pivoted to the seat frame, and a second leg frame pivoted to the first leg frame and formed with a slide member that extends slidably into the elongated groove. When in an unfolded state, the slide member extends along the elongated groove to the front end portion of the seat frame. When in a folded state, the slide member extends along the elongated groove to the rear end portion of the seat frame. A locking unit includes a stop member disposed below the seat frame and mounted pivotally to the front end portion of the seat frame about a horizontal pivot axis. The stop member is formed with an upwardly extending stop protrusion. A biasing member biases the stop member to move the stop protrusion upwardly adjacent to the elongated groove to arrest rearward movement of the slide member along the elongated groove when the chair frame is in the unfolded state, thereby preventing untimely folding of the chair frame.

Claims

1. A foldable chair frame, comprising:

a seat frame having a front end portion and a rear end portion, and being formed with a pair of elongated grooves which extend from said front end portion to said rear end portion;

a first leg frame which extends forwardlv and downwardly from said rear end portion of said seat frame, said first leg frame having an upper end mounted pivotally to said rear end portion of said seat frame, a lower end adapted to be supported on a ground surface, and an intermediate section between said upper and lower ends;

a second leg frame which has an upper end formed with a pair of slide members slidably projecting into said elongated grooves of said seat frame, a lower end adapted to be supported on the ground surface, and an intermediate section pivotably coupled to said intermediate section of said first leg frame;

said chair frame being movable between an unfolded state, in which said seat frame is substantially horizontal, and said slide members of said second leg frame reside within said elongated grooves proximate said front end portion of said seat frame, and a folded state, in which said seat frame is substantially upright, and said slide members of said second leg frame reside within said elongated grooves proximate said rear end portion of said seat frame; and

a locking unit mounted on said seat frame and including;

a stop member disposed below said seat frame and mounted pivotally to said front end portion of said seat frame about a horizontal pivot axis, said stop member being formed with an upwardly extending stop protrusion, and

a biasing member for applying a biasing force to said stop member such that the application of said biasing force to said stop member movably disposes said stop protrusion to a point adjacent one of said elongated grooves so as to impede sliding movement of one of said slide members residing in said one of said elongated grooves away from said front end portion of said seat frame along said one of said elongated grooves when said chair frame is in said unfolded state, thereby preventing untimely folding of said chair frame, and such that the application to said stop member of a force in opposition to said biasing force movably disposes said stop protrusion to a point distal said one of said elongated grooves so as to permit sliding movement of said one of said slide members away from said front end portion of said seat frame along said one of said elongated grooves, when said chair frame is to be folded into said folded state,

said locking unit further including a pivot seat having a parallel pair of pivot lobes that extend downwardly from said front end portion of said seat frames and a pivot pin extending through said stop member and said pivot lobes for mounting said stop member pivotally to said seat frame,

said stop member including a front section extending forwardly of said pivot pin, and a rear section extending rearwardly of said pivot sin, said stop member being formed with a horizontal abutment wall, at said rear section, said stop protrusion being formed at said front section, said biasing member being formed as a torsion spring which is disposed between said pivot lobes and which has said pivot pin extending therethrough, said torsion spring having one end abutting against said seat frame and another end abutting against said horizontal abutment wall for biasing said rear section downwardly, thereby resulting in upward pivoting movement of said front section about said pivot pin to result in upward movement of said stop protrusion,

said stop protrusion being formed as a flat upright plate, and having a first edge which abuts against said one of said slide members to prevent rearward movement of said one of said slide members in said one of said elongated grooves when said chair frame is in the unfolded state.

2. The foldable chair frame according to claim 1, wherein said first edge of said stop protrusion is substantially vertical, said stop protrusion further having a second edge that inclines rearwardly and downwardly from a top end of said first edge to permit said one of said slide members to slide past second edge and push said front section of said stop member downwardly against biasing action of said biasing member when said chair frame is unfolded.