Foldable Chair Frame Assembly

Abstract

A foldable chair frame assembly comprising a pair of vertically extendable side frame members and a pair of connection member assemblies connecting said side frame members so as to cause them to approach each other when the chair is folded up and, when one sits on the chair, expanding in the form of the letter X, thereby reinforcing side frame members against the load applied thereon by the sitter.

Description

BACKGROUND OF THE INVENTION

This invention relates to a chair frame assembly and more particularly to a foldable chair frame assembly.

Heretofore, there have been used various types of foldable chair frame assembly. However, none of them afforded stability to the sitter and could be easily folded.

SUMMARY OF THE INVENTION

It is accordingly the object of this invention to provide a novel type of easily foldable chair frame assembly which affords good stability to the sitter and, where required, makes up a convenient foldable chair capable of being used as a stool with the arm portions folded downward.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 to 4 illustrate chairs using a foldable chair frame assembly according to this invention: FIG. 1 is a perspective view, partly in section, of an expanded chair; FIG. 2 is a perspective view of a folded chair; FIG. 3 is a perspective view, partly in section, of a chair used as a stool; and FIG. 4 is a plan view with part of FIG. 3 enlarged.

DETAILED DESCRIPTION OF THE INVENTION

There will now be described by reference to the appended drawings the foldable chair frame assembly of this invention. Throughout the figures, numeral 1 represents a pair of side frame members facing each other, as illustrated in FIGS. 1 and 3, at a prescribed space when used. Each side frame member comprises a bottom tube 2 having both ends bent upward at an angle of substantially 90.degree. and guide rods 3 each coaxially connected at the lower end to said bent end portion of the bottom tube 2. Said guide rod 3 has a smaller outer diameter than that of the end portion of the bottom tube 2, so that at that part of the guide rod 3 which contacts the end portion of the bottom tube 2 is formed a stepped or stopper portion 4. Said guide rod 3 is slidably inserted into a leg tube 5 slightly shorter than said guide rod 3 and capable of sliding vertically along its peripheral surface. When used, the leg tube 5 has its lower end limited in its downward slide by the aforesaid stepped or stopper portion 4, and its upper end disposed a little below the top end of said guide rod 3. Between the upper ends of the forward and rear leg tubes 5 on each side of the chair is horizontally disposed a beam rod 6 by being connected at both ends to said upper ends of the forward and rear leg tubes 5, said beam rod 6 being intended to have a seat cloth 18 stretched across them. To both upper ends of the forward and rear leg tubes 5 are connected both lower ends 8 of a vertically reverse U-shaped arm tube 7 outwardly rotatable through an angle of 180.degree. so as to be folded. The forward and rear upright portions 8 of each arm tube 7 are provided at the bottom ends with pins 9 horizontally projecting in the mutually facing direction above the leg tubes 5. To that side of the upper end of each leg tube 5 which faces the inside of the chair is fitted an upwardly projecting bearing member 10, into which there is inserted the aforesaid pin 9 through a spring washer 11, thereby permitting the outward folding of the arm tube 7. To the upper horizontal portion of the arm tube 7 is fitted an arm rest plate 12 made of wood or plastics material. Behind both arm tubes 7 are set upright support pillars 13 coaxially and integrally with the rear upright portions of both arm tubes 7, said support pillars 13 being intended to have a back cloth 17 stretched across them.

Numeral 14 represents a pair of connection rod assemblies arranged at a prescribed space. Said connection rod assembly 14 is formed of a pair of connection rods 16 which are pivoted by a common shaft pin 15 at the central part, which are so bent as to be disposed horizontal when the chair legs are opened, said connection rod assembly 14 taking the form of the letter X. Each connection rod assembly 14 is connected at the upper ends to the beam rods 6 of said side frame members 1 and at the lower ends to the bottom leg tubes 2 of said side frame members 1. Thus the paired connection rod assemblies 4 can rotate about the aforesaid central part to hold or expand the frame assembly.

Across the support pillars 13 of the paired side frame members are stretched, as illustrated in FIG. 1, the flexible back cloth 17 made of canvas or PVC (polyvinyl chloride) leather with said support pillars 13 inserted into the hollow lug portions 17a formed on both sides of said back cloth. Also across the paired beam rods 6 is stretched the sheet fabric 18 made of the same material as that of the back cloth 17. Thus is formed a foldable chair. Under this condition, the paired side frame members are joined by said connection rod assembly 14 taking the form of the letter X. Accordingly the load applied by the sitter's weight so acts as to strengthen connection between the bottom tubes 2 and arm tubes 7. Further, the guide rods 3 connected to the bottom tubes 2 are disposed perpendicular to the floor surface, namely, are aligned with the direction in which the sitter's weight is applied, thereby stabilizing the chair to the sitter.

When it is desired to fold up the above-mentioned collapsible chair, the back cloth 17 is first taken off one of the support pillars 13. With the horizontal bottom tube 2 of one side frame member 1 stepped down, for example, with a foot, there is pulled up by hand the arm tube 7 or arm plate 12 of said side frame member 1 or another part of the frame member 1 connected to said arm tube 7, for example, the leg tube 5 or beam tube 6. As the result, the leg tube 5 of the aforesaid stepped down side frame member 1 slides upward along the guide rods 3. The leg tube 5 of the other side frame member 1 similarly slides upward along the associated guide rod 3 due to the connection rod assemblies 14 being rotated about the common shaft pin 15. Further, said rotation causes said other side frame member 1 to move up to the first mentioned stepped down side frame member 1, thus finally bringing the chair as a whole to a flat folded state with said two side frame members 1 closely drawn to each other. Thereafter, the arm tubes 7 are rotated outward through an angle of 180.degree., as illustrated in FIG. 2, thereby completing the folding operation. When it is desired to use again the chair thus folded up, it is only required to conduct an opening work exactly reverse to the aforesaid folding operation.

The above-mentioned folding and setting up of the collapsible chair of this invention can be effected quite smoothly, because the leg tubes 5 are designed to slide along the associated guide rods 3 and said guide rods 3 are made slightly longer than said leg tubes 5.

Where it is desired to use the chair of the aforesaid arrangement as a stool, the back cloth 17 is taken off one of the support pillars 13, and the chair is brought to a folded state shown in FIG. 2 by the previously described folding operation. Then the beam rods 6 are gripped by hand to separate both side frame members 1, causing the chair legs to be opened with the top ends of the guide rods 3 slightly projected from those of the leg tubes 5.

Further, where required, the back cloth 17 may be stretched across the rear guide rods 3. In such case, said rear guide rods 3 are preferred to be slightly longer than the forward ones.

Claims

What is claimed is:

1. A foldable chair frame assembly comprising a pair of spatially disposed side frame members consisting of bottom leg tubes each having both end portions bent upward, guide rods having a smaller diameter than said bent end portions and connected thereto at the lower end with a stopper portion formed at that part of said guide rods which is contacted by said bent end portions, two pairs of forward and rear leg tubes slightly shorter than said guide rods inserted there-through and slidable along said guide rods, the sliding of said leg tubes in one direction being limited by having the lower ends contacted by said stopper portions, a pair of beam rods each extended across the upper ends of each pair of said forward and rear leg tubes, and arm tubes outwardly swingable through an angle of 180.degree. with the downwardly bent portions pivotally connected to the upper ends of said forward and rear leg tubes; and spatially disposed connection means each having a pair of connection rods pivotally connected and acrossed to each other at the center, the connection rod being connected at the bottom end to the bottom tube of one of said side frame members and at the upper end to the beam rod of the other of said side frame members, whereby when the chair is to be folded up, the arm tubes are each rotated outwardly through an angle of 180.degree., the leg tubes slide along the guide rods inserted therethrough, and the connection rods are rotated about the central pivotal portion so as to cause both side frame members to be closely drawn to each other.

2. The foldable chair frame assembly according to claim 1 wherein the two arm tubes have two pillars set upright coaxially with the rear bent end portions of said arm tubes between which a back cloth is to be stretched.

3. The foldable chair frame assembly according to claim 2 which further has a seat cloth stretched across the two beam rods and a back cloth stretched across the two pillars.

4. The foldable chair frame assembly according to claim 1 wherein the two connection rod assemblies have a common shaft pin for pivotally connecting the pair of connection rods constituting said connection rod assemblies.

5. The foldable chair frame assembly according to claim 4 wherein each of said connection rod has a central part which is so bent as to be disposed horizontal when the chair frame assembly is expanded.

6. The foldable chair frame assembly according to claim 1 wherein, of the four guide rods, the two rear ones are longer than the two forward ones.