Patent Publication Number: US-6709050-B2

Title: Slide rail-type metal foldable chair

Description:
BACKGROUND OF THE INVENTION 
     The present invention is related to a slide rail-type metal foldable chair. The front chair leg is: 
     A conventional slide rail-type foldable chair is made of wooden material. This is the wooden material can be easily milled and processed. Such slide rail-type folding mechanism makes it easy to fold and unfold the chair. When operated, a user&#39;s hand is protected from being clamped by the front and rear chair legs in the pivot corner. However, the wooden chair has heavy weight and the pattern of the wooden chair is limited. 
     It has been tried by manufacturers to apply slide rail-type folding mechanism to metal foldable chair. However, it is troublesome and time-consuming to mill the metal tube (generally iron tube or stainless steel tube) with slide rail. Therefore, up to now, the slide rail-type folding mechanism still cannot be fully applied to the non-wooden foldable chairs. 
     SUMMARY OF THE INVENTION 
     It is therefore a primary object of the present invention to provide a slide rail-type metal foldable chair in which the front and rear chair legs are preferably made of rustproof and light aluminum alloy or other metal. The foldable chair of the present invention has light weight and can be smoothly operated. The foldable chair can be folded into a plane state without clamping the user&#39;s hand. The number of the pivoted sections of the seat and the front and rear chair legs exposed to outer side is minimized. 
     The present invention can be best understood through the following description and accompanying drawings wherein: 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side view of the present invention; 
     FIG. 2 is a front view of the present invention; 
     FIG. 3 is a top view of the seat of the present invention; 
     FIG. 4 is a right view according to FIG. 3; 
     FIG. 5 is a front view of the seat of the present invention, showing the pivot shafts thereof; 
     FIG. 6 is a sectional view taken along line  6 — 6  of FIG. 3; 
     FIG. 7 is a sectional view taken along line  7 — 7  of FIG. 3; 
     FIG. 8 is a sectional view taken along line  8 — 8  of FIG. 3; 
     FIG. 9 is a sectional view taken along line  9 — 9  of FIG. 3; 
     FIG. 10 is a sectional view taken along line  10 — 10  of FIG. 2, showing the back of the present invention; 
     FIG. 11 is a sectional view taken along line  11 — 11  of FIG. 2, showing the back of the present invention; 
     FIG. 12 shows the slide rail washer of the present invention; 
     FIG. 13 is a top view according to FIG. 12; 
     FIG. 14 is a sectional view taken along line  14 — 14  of FIG. 13; 
     FIG. 15 is a right view according to FIG. 13; 
     FIG. 16 shows the slide magazine of the present invention; 
     FIG. 17 is a top view according to FIG. 15; 
     FIG. 18 is a partial sectional view of the slide magazine; 
     FIG. 19 shows the connection between the seat, the front chair leg, and the rear chair leg: 
     FIG. 20 is a front view of the front chair leg; and 
     FIG. 21 is a sectional view taken along line  21 — 21  of FIG.  20 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Please refer to FIGS. 1 and 2. The present invention includes a front chair leg  1 , a rear chair leg  2 , a back  3  and a seat  4 . 
     The front and rear chair legs  1 ,  2  are tubular bodies made of aluminum alloy (or other metal). The front chair leg  1  is pivotally connected with the rear chair leg  2  at pivot point A. The inner side of the front chair leg  1  is formed with an elongated slide rail  11  above the pivot point A. The slide rail passes through the inner wall of the front chair leg. A slide rail washer  5  (as shown in FIGS. 12 to  15 ) is laid on the opening of the slide rail  11 . The slide rail washer  5  has a substantially I-shaped cross-section. When formed, two sides of the slide rail washer  5  are slightly outward curved. When laid on the opening of the slide rail  11 , the slide rail washer has a set outward expanding supporting and fixing elasticity so as not to detach from the opening. The back  3  is inserted in upper side of the front chair leg  1 . The back  3  encloses therein a metal tube (as shown in FIGS. 2 and 10 to  11 ). The back is composed of a U-shaped metal tube  30  coated with a plastic back. Two sides of the metal tube  30  has downward extending insertion legs  31  for fixedly inserting in the top openings of two sides of the front chair leg  1 . After the slide magazine  6  is placed into the front chair leg  1  and the front chair leg  1  is completely assembled with the rear pivot shaft  41  of the seat  4 , the back  3  is assembled with the front chair leg  1 . 
     The slide magazine  6  (as shown in FIGS. 16 to  18 ) is up and down slidably disposed in the front chair leg  1 . The main body of the slide magazine  6  has a U-shaped cross-section. When assembled, the opening faces the interior of the front chair leg  1 . The bottom end of the slide magazine  6  is formed with a fitting hole  61  for the rear pivot shaft  411  of the seat  4  to fit therethrough and locate therein. The upper end of the slide magazine is formed with a C-shaped hooking notch  62 . An operator can use an iron wire or other elongated tool to hook the hooking notch  62  so as to insert the slide magazine  6  into the front chair leg  1  for assembling with the rear pivot shaft  41  of the seat  4 . The tool can be easily detached from the hooking notch  62 . FIG. 19 shows the assembly of the rear pivot shaft  41  of the seat  4  and the slide rail washer  5  and slide magazine  6  of the slide rail  11  of the front chair leg  1 . When the chair is unfolded, the seat  4  is horizontally positioned and the slide rail  11  is covered by the internal slide magazine  6 . 
     The rear chair leg  2  is pivotally connected with the front chair leg  1  at pivot point A. The inner wall of top end of the rear chair leg  2  is formed with a pivot hole  21  for the front pivot shaft  42  of the seat  4  to fit therethrough. The pivot bole only passes through the inner wall of the rear chair leg  2 . The front pivot shaft  42  of the seat  4  extends into the tube of the rear chair leg  2  and is located therein by a retainer ring  22  (as shown in FIG.  19 ). Therefore, the pivot point is not exposed to outer side. A cap  23  is fitted with top end of the rear chair leg  2  to seal the same as shown in FIG.  1 . 
     Referring to FIGS. 1 to  9  and  19 , the periphery of the seat  4  encloses therein a metal tube  40 . When formed, the mesh seat face  43  is at the same time fixed. Accordingly, the seat  4  encloses therein the metal tube  40  and the has the mesh seat face  43 . The rear pivot shaft  41  for assembling with the front chair leg  1  and the front pivot shaft  42  for assembling with the rear chair leg  2  are respectively disposed on lateral sides of the seat  4 . The front and rear pivot shafts  42 ,  41  respectively pass through the enclosed metal tube  40  and are integrally combined when molding the seat  4 . The outward extending length of the rear pivot shaft  41  is longer than the length of the front pivot shaft  42 . The rear pivot shaft  41  is inserted in the fitting hole  61  of the slide magazine  6  in the slide rail  11  of the front chair leg  1 . The front pivot shaft  42  is passed through the inner wall of top end of the rear chair leg  12  and located therein by the C-shaped retainer ring  22 . 
     Referring to FIG. 1, the present invention has light weight so that it can be easily operated. When the seat  4  is horizontally positioned, the rear pivot shaft  41  of the seat  4  makes the slide magazine  6  in the front chair leg  1  move downward. When the rear pivot shaft  41  is positioned at the bottom end of the slide rail  11 , the slide rail opening is covered by the internal slide magazine  6 . 
     According to the above arrangement, the present invention has the following advantages: 
     1. The slide rail enables a user to smoothly operate the foldable chair. The chair is light and can be folded into a plane state without clamping the user&#39;s hand. The slide rail opening is automatically covered so that when the seat is positioned horizontally, the slide rail is not exposed to outer side. 
     2. The back and the seat both enclose therein metal tubes. In addition, the seat is integrally formed with mesh seat face with good ventilation effect. 
     3. The front and rear pivot shafts of the seat for pivotally connecting with the front and rear chair legs are passed through and fixed in the internal metal tubes so that the foldable chair is firmer and able to bear greater load. 
     4. The pivoted sections of the seat and the front and rear chair legs are all hidden. 
     5. Only the pivot point A of the front and rear chair legs is exposed. 
     6. When placing the seat horizontally for use, it is safe to press down the seat face from front side or rear side thereof. The pressure is even so that the seat will not be tilted down to cause danger. 
     The above embodiment is only used to illustrate the present invention, not intended to limit the scope thereof. Many modifications of the above embodiment can be made without departing from the spirit of the present invention.