Patent Publication Number: US-6669281-B1

Title: Pull rod-type foldable chair structure

Description:
BACKGROUND OF THE INVENTION 
     The present invention is related to a pull rod-type foldable chair structure. 
     There are various kinds of foldable chairs. The early foldable chairs are made of wooden material. The later foldable chairs made of metal and plastic materials instead of the wooden material. The metal-made foldable chair has heavy weight and tends to rust. Therefore, the metal-made chair needs baking finish. This leads to high cost. Accordingly, it is trend to manufacture the chair frame of the foldable chair from aluminum alloy. However, the metal-made foldable chair has limited plasticity so that it is hard to manufacture the metal-made foldable chair with curved pattern. Therefore, it is developed to manufacture the seat and back of the foldable chair from plastic material by molding. The molded seat and back are assembled with chair frame made of metal or aluminum alloy so as to achieve solid curved pattern of the chair. 
     However, the conventional foldable chairs still have some shortcomings as follows: 
     1. The foldable chair lacks buffing design. Therefore, when folding or unfolding the foldable chair, the front and rear chair legs often instantaneously stretches or collapses. Therefore, a user, especially a child is very easy to be clamped and injured by the foldable chair. 
     2. In the case that the foldable chair is equipped with an oil cylinder to avoid instantaneous folding or unfolding, the cost will be too high and the foldable chair will have too heavy weight. 
     3. It is troublesome to assemble the seat and back with the chair frame of the foldable chair. Moreover, the fixing screws often protrude from the chair frame to ruin the appearance of the chair. 
     4. It is troublesome to assemble the seat and back of the foldable chair so that the production efficiency is lowered. 
     5. When stored, generally the foldable chairs are upright leant on each other. Therefore, the foldable chairs will occupy much room. 
     6. The foldable chairs cannot be horizontally stacked. In the case that the foldable chairs are horizontally stacked, they tend to slip and fall down. This may lead to damage of the chairs or even injury of persons. 
     7. The ground-contacting blocks of the foldable chair are hard. Such hard ground-contacting blocks tend to scrape wooden and plastic floorboard. 
     8. The frictional force between the hard ground-contacting blocks of the foldable chair and the ground is weak. Therefore, the foldable chair tends to slip on the ground. 
     SUMMARY OF THE INVENTION 
     It is therefore a primary object of the present invention to provide a pull rod-type foldable chair structure in which the chair frame, the seat and the back can be quickly assembled. The transverse beam of the chair leg is equipped with elastic ground-contacting blocks. Therefore, the chair can be used on any floorboard made of any material such as wooden, plastic and stone floorboards. The ground-contacting block will not scrape the floorboard and the chair can be more stably placed on the ground. 
     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 side view of the present invention, showing the folding thereof; 
     FIG.  4 . shows that the foldable chairs of the present invention is horizontally stacked; 
     FIG.  5 . is a side view of the seat of the present invention; 
     FIG.  6 . is a top view of the seat of the present invention; 
     FIG.  7 . is a bottom view of the seat of the present invention; 
     FIG.  8 . is a sectional view taken along line a—a of FIG. 6; 
     FIG.  9 . is a sectional view taken along line b—b of FIG. 6; 
     FIG.  10 . is a sectional view taken along line c—c of FIG. 6; 
     FIG.  11 . is a side view of the support board of the present invention or assembling the seat with the chair frame; 
     FIG.  12 . is a rear view of the support board of the present invention; 
     FIG.  13 . is a top view of the support board of the present invention; 
     FIG.  14 . is a side view of the right pull rod of the rear chair leg of the present invention; 
     FIG.  15 . is a top view of the right pull rod of the rear chair leg of the present invention; 
     FIG.  16 . is a rear view of the right pull rod of the rear chair leg off the present invention; 
     FIG.  17 . is a side view of the left pull rod of the rear chair leg of the present invention; 
     FIG.  18 . is a top view of the left pull rod of the rear chair leg of the present invention; 
     FIG.  19 . is a rear view of the right pull rod of the rear chair leg of the present invention; 
     FIG.  20 . shows the ground-contacting block seat body of the present invention; 
     FIG.  21 . is a left view according to FIG. 20; 
     FIG.  22 . is a top view according to FIG. 20; 
     FIG.  23 . is a right view according to FIG. 20; 
     FIG.  24 . is a bottom view according to FIG. 20; 
     FIG.  25 . shows the ground-contacting block of the present invention; 
     FIG.  26 . is a top view according to FIG. 25; 
     FIG.  27 . is a right view according to FIG. 25; 
     FIG.  28 . is a bottom view according to FIG. 25; and 
     FIG.  29 . is a sectional view of the assembly of the ground-contacting block and ground-contacting block seat body of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Please refer to FIGS. 1 to  3 . The present invention includes a front chair leg  1 , a rear chair leg  2 , a seat  3 , a back  4 , two pull rods  5 , two support boards  6  and ground-contacting blocks  7 . 
     The bottom transverse beam of the front chair leg  1  is provided with ground-contacting blocks  7  and ground-contacting block seat bodies  70  coupled with the ground-contacting blocks  7 . Via a pivot member  11 , the inner side of middle section of the front chair leg  1  is pivotally connected with a pivot hole  61  near the middle section of the support board  6 . The outer or inner side of upper section of the front chair leg is formed with engaging holes  10  for engaging with the back  4 . Via a pivot member  12 , the outer side of the front chair leg  1  between the pivot member  11  and the back  4  is pivotally connected with the pull rod  5  telescopically inserted in the top section of the rear chair leg  2 . 
     The bottom transverse beam of the rear chair leg  2  is provided with ground-contacting blocks  7  and ground-contacting block seat bodies  70  coupled with the ground-contacting blocks  7 . The inner side of front edge of the rear chair leg  2  is provided with a pivot board  21  which via a pivot member  13  is pivotally connected with a pivot hole  62  of the rear section of the support board  6 . 
     Referring to FIG. 5, the seat  3  is made by molding. The bottom of two sides of the seat  3  is formed with insertion grooves  31 . The insertion hooks of the J-shaped support boards  6  are inserted in the insertion grooves  31 . The lateral walls of the support boards  6  are formed with through holes  63 ,  64 . Fixing members such as screws are passed through the through holes  63 ,  64  to fix the support boards  6  with the seat  3 . 
     Referring to FIGS. 11 to  13 , the support board  6  is substantially J-shaped. The inner edge of bottom wall of the support board  6  is bent to form an insertion wall  60  for inserting into the insertion groove  31  of the seat  3 . The support board  6  is formed with two through holes  63 ,  64  for fixing the seat  3  and a pivot hole  61  for pivotally connecting with the front chair leg  1  and a pivot hole  62  for pivotally connecting with the pivot board  21  of the rear chair leg  2 . 
     Referring to FIGS. 1 and 2, two sides of the back  4  are formed with assembling cavities  40  for two lateral leg rods of the front chair leg  1  to insert therein. A resilient engaging member  41  is disposed in each assembling cavity  40 . The engaging member  41  is engaged in the engaging hole  10  of the leg rod of the front chair leg  1 , whereby the back  4  can be quickly and easily assembled with the front chair leg  1 . 
     Referring to FIGS. 14 to  19 , the left and right pull rods  5  are symmetrical to each other. The upper end of the pull rod  5  is a pivot head  50  formed with a pivot hole  51  for pivotally connecting with the pivot member  12  of the front chair leg  1 . The front lower edge of the pivot head  50  is formed with a locating recess  52 . The rear end of the pivot head  50  is formed with a locating projecting block  53 . The locating projecting block  53  of the pivot head  50  of the pull rod  5  of one foldable chair can be placed and located in the locating recess  52  of the pivot head  50  of the pull rod  5  of another foldable chair. The pivot head  50  and the telescopic rod body  54  of the pull rod  5  contain a bending angle. Moreover, a bending neck section  55  is formed between the pivot head  50  and the telescopic rod  54 . When the telescopic rod  54  is telescopically inserted in the top opening of the rear chair leg  2 , the pivot head  50  at upper end of the pull rod  5  is bent outward and leant on outer side of the front chair leg  1 . 
     Referring to FIGS. 20 to  24 , the ground-contacting block seat body  70  has a holding mouth  701  facing upward for holding the transverse beam of the chair leg. An insertion post  702  is formed in the seat body  70  for inserting into a locating hole A 1  of the bottom of the transverse beam A as shown in FIG.  29 . In addition, the inner face of the bottom of the seat body  70  is formed with a dented face  703 . The ground-contacting block  7  having elasticity and hardness softer than the seat body  70  is positioned in the dented face  703 . The bottom of the seat body  70  is formed with at least one perforation  704 . The projecting block  72  of the ground-contacting block  7  protrudes through the perforation  704  from the bottom of the seat body  70  for contacting with the ground. 
     Referring to FIGS. 25 to  28 , the ground-contacting block  7  is formed with a through hole  71  for the insertion post  702  of the dented face  703  of the seat body  70  to pass therethrough. At least one projecting block  72  downward protrudes from the bottom of the ground-contacting block  7 . The projecting block  72  is fitted through the perforation  704  of the seat body  70  to protrude from the bottom of the seat body  70  for contacting with the ground. The ground-contacting block  7  is fixedly clamped between the dented face  703  of the seat body  70  and the transverse beam of the chair leg. The insertion post  702  is fitted through the ground-contacting block  7  and inserted in the locating hole A 1  of the transverse beam A so as to firmly assemble the ground-contacting block  7  with the seat body  70  and the transverse beam A. 
     According to the above arrangement, the present invention has the following advantages: 
     1. The rear chair leg is pivotally connected with the front chair leg via the pull rod. Therefore, when folding or unfolding the rear chair leg, the pull rod  5  provides a pneumatic buffing effect. 
     2. The pivot head  50  of the pull rod  50  is formed with a locating recess  52  and a locating projecting block  53 . When the chairs are horizontally stacked, the locating projecting blocks  53  and the locating recesses  52  of the chairs are engaged with each other. Therefore, the chairs are stably and safely located without slippage. 
     3. It is convenient and quick to assemble the seat  3 , the support boards  6 , the front chair leg  1  and the rear chair leg  2 . Therefore, the production efficiency of the chair is high and the manufacturing cost is lowered. 
     4. The back  4  is engaged and assembled with the front chair leg  1  by the engaging member  41  without using any screw. Therefore, the problem of protrusion of the screw is avoided and the back  4  can be quickly and easily assembled with the front chair leg  1 . 
     5. The seat body  70  is hard so that it is firmly assembled with the chair leg without easy detachment. The softer and elastic ground-contacting block  7  is directly located in the seat body  70  and protrudes therefrom for contacting with the ground. Therefore, the ground-contacting block  7  will not scrape the floorboard and the frictional force between the ground-contacting block  7  and the ground is greater. Moreover, the ground-contacting block  7  can more stably attach to the ground. 
     6. The quality of the chair is better. 
     7. The safety in use of the foldable chair is ensured. 
     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.