Patent Publication Number: US-5897161-A

Title: Two-directionally folding chair

Description:
SPECIFICATION 
     The invention relates to a folding chair comprising a seat supported by righthand and lefthand front legs as well as righthand and lefthand rear legs, and a back-rest associated with said rear legs. 
     Folding chairs are needed particularly at functions and concerts where the number of visitors fluctuates widely. Such fluctuations are accommodated easily by the flexible and rapid setting up of folding chairs. 
     In general, prior folding chairs fold in one direction only. Thus, when folded, the righthand legs and the lefthand legs are placed against each other by pairs and the seat is turned up or down. Similarly, the front and rear legs may he interconnected by means of rotary joints in cross fashion, said legs to be placed against each other by pairs as the chair is folded. 
     In both solutions, the problem is that the chairs can be folded in one direction only, which makes space saving stowage more difficult. In addition, the spatial form of the folded chair is hardly compact, which may cause adjacent chairs to get entangled or stuck to each other. 
     It is the object of the present invention to provide a folding chair which is stable, provides safe seating and folds together in a space saving manner. 
     This object is achieved by the front legs being movably joined to the rear legs in rotary joints provided at one end thereof and by the front legs being joined to each other for relative movement. In one preferred embodiment, this is accomplished by the front legs being interconnected by intersecting front cross braces and the rear legs being interconnected by intersecting rear cross braces, by said cross braces being relatively movably joined at centrally located rotary joints, and by said cross braces being adapted to be moved relative to the associated front or rear legs in sliding guide means. 
     By the aforesaid measures, the righthand legs and the lefthand legs are placed against each other as the chair is folded. For folding the chair in an additional direction, the front legs and the rear legs are interconnected by at least one movably arranged brace each. Preferably, the front legs, and the rear legs, are interconnected by two movably disposed intersecting braces. Each brace is secured at one of its ends in a joint and is guided at its other end in sliding guide means. The braces are additionally interconnected by rotary joints disposed at their points of intersection. 
    
    
     Further advantageous measures are described in the dependent claims. The invention is shown in the attached drawing and is described in greater detail hereinbelow. 
     FIG. 1 shows a sideview of an erected chair comprising a seat and legs having tapered portions at their top ends to clampingly hold a back-rest, said legs being interconnected by rotary joints ar their top ends; 
     FIG. 2 shows a front view of a chair according to FIG. 1 with intersecting or crossing braces which have their top ends connected to front legs by sliding guide structures and their bottom ends conncted to the front legs by rotary joints; 
     FIG. 3 shows a rear view of a chair according to FIG. 1 with its legs held in a spaced relationship by cross braces, said legs having their top ends guided in sliding guide structures for connection to the rear legs and their bottom ends connected to the rear legs through rotary joints; 
     FIG. 4 shows on an enlarged scale a portion X1 of FIG. 3 where a seat brace has a projection at a rear end thereof, said projection being passed through a recess provided at the top end of the rear braces and comprising a guide pin engaging a recess provided on a rear leg; 
     FIG. 5 shows on an enlarged scale a portion X2 of FIG. 2 in which seat brace has a seat brace recess adapted to connect with a brace recess in the braces; 
     FIG. 6 shows a front view of the chair in FIG. 2 in a partly folded condition, with the back rest and the seat removed; 
     FIG. 7 shows a front view of the chair shown in FIG. 6 in a completely folded condition; 
     FIG. 8 shows a side view of the chair shown in FIG. 1 in a collapsed condition; 
     FIG. 9 shows a plan view of the back rest comprising a web of fabric wrapped around two tubular members; 
     FIG. 10 shows the plan view of a seat having seat supports wrapped by a web of seat fabric, said seat fabric being cut out in the area of the seat brace recesses; 
     FIG. 11 shows a side view of a seat brace having a seat brace recess and a projection at its left end, said projection carrying a guide pin; 
     FIG. 12 shows a plan view of the seat brace shown in FIG. 11; 
     FIG. 13 shows a rear view of the chair illustrated in FIG. 6 with recesses in the braces and in the rear legs for mounting the seat; and 
     FIG. 14 shows a plan view of the chair collapsed and folded as illustrated in FIGS. 7 and 8, showing said legs to be L-shaped in section and to be interconnected by joints and braces. 
    
    
     Referring to FIG. 1, there is shown a side view of a folding chair 10. Folding chair 10 has two front legs 11a and 11c and two rear legs 11b and 11d. Front legs 11a and 11c are inclined at an angle α relative to rear legs 11b and 11d, which stand in a substantially vertical position. Lefthand legs 11a and 11b are connected at their top ends by a rotary joint 12a, which allows them to be placed at an angle relative to each other. Righthand legs 11c and 11d are similarly interconnected by a rotary joint 12b. In their mutually inclined position, the pair of lefthand legs 11a, 11b and the pair of righthand legs 11c, 11d form a right triangle with floor 32. 
     FIG. 8 shows a side view of chair 10 with its righthand legs 11c and 11d folded to lie against each other, as are lefthand legs 11a and 11b. Legs 11a, 11b and 11c, 11d, respectively, can be placed against each other with their long sides engaging so as to create a compact assembly which lends itself to space saving stowage. 
     At their top ends, the four legs 11a, 11b, 11c and 11d have tapered portions 13a, 13b, 13c and 13d, respectively. These tapers are trianglular in shape, with the triangles pointed to the top. The sides adjacent to the tip angle of said triangular tapers 13a, 13b, 13c, 13d are linear extensions of the outer edges of legs 11a, 11b, 11c, 11d, whereas the hypotenuses of said triangular tapers 13a, 13b, 13c, 13d face each other by pairs. 
     The hypotenuse of taper 13a on lefthand rear leg 11a is arranged to face the hypotenuse of taper 13b on lefthand front leg 11b. The hypotenuses of righthand legs 11c, 11d are similarly oriented. Because of this arrangement, the hypotenuses of tapers 13a, 13b and of tapers 13c, 13d engage each other face to face when legs 11a to 11d are in their mutually angled relative orientation. 
     As tapers 13a, 13b and 13c, 13d engage each other face to face, a back-rest can be clampingly secured between them. Back-rest 14 is released by folding legs 11a, 11b and 11c, 11d down against each other. 
     FIG. 2 shows a front view of folding chair 10. For placing lefthand legs 11a, 11b against righthand legs 11c, 11d in a space saving arrangement, front legs 11a, 11c are interconnected by movable cross braces 15a, 15c, and rear legs 11b, 11d are similarly interconnected by cross braces 15b, 15d. 
     Front cross brace 15a slants upwardly from the bottom end of lefthand front leg 11a to righthand front leg 11c. Front cross brace 15c slants in a mirror-image form so that cross braces 15c, 15a intersect. Rear cross braces 15b, 15d extend similarly to interconnect rear legs 11b, 11d. At the point of intersection cross braces 15a, 15c are interconnected by a rotary joint l9a; at their point of intersection, rear cross braces 15b, 15d have a rotary joint 19b. 
     The top ends of cross braces 15a, 15b, 15c and 15d are slidingly guided in guide structures 17a, 17b, 17c and 17d. In accordance with the invention, said guide structures 17a, 17b, 17c, 17d comprise recesses or slots extending upwardly in parallel with the long sides of legs 11a, 11b, 11c, 11d. Said slots guide pins 33a, 33b, 33c and 33d connected with legs 11a, 11b, 11c, 11d. At their bottom ends, cross braces 15a, 15b, 15c, 15 are secured to legs 11a, 11b, 11c, 11d through pivoting joints 16a, 16b, 16c and 16d. 
     As shown in FIGS. 6 and 7, the top ends of cross brace 15a, 15b, 15c, 15d are free to slidingly move upwards as righthand legs 11c, 11d are placed against lefthand legs 11a, 11b. When the legs engage each other along their long sides, as shown in FIG. 7, pins 33a, 33b, 33c, 33d abut the top ends of guide slots 17a, 17b, 17c, 17d. 
     FIGS. 1 to 5 show the manner of securing seat 20 in place. Seat 20 extends approximately in parallel with floor 32. The rear corners of seat are connected flush with rear legs 11b, 11d. In the central portions of the side edges, seat 20 is connected wiht front legs 11a, 11c. Seat 20 is carried by two longitudinally extending seat supporting bars 21a, 21b that have a web of seat fabric 28 strung between them. 
     Seat supporting bars 21a, 21b preferably consist of lengths of L-section bar material. Seat 20 is secured to front legs 11a, 11c by means of slot-shaped recesses 23 provided at the top ends of the side edges of cross braces 15a, 15c, as shown in FIGS. 5 and 6. 
     When spaced to the maximum extent, recesses 23 extend substantially in a parallel offset relationship to front legs 11a, 11c. In this maximum position, recesses 23 of cross braces 15a and 15c, respectively, extend downwardly from the top edges thereof. In order to obtain optimum stability, recesses 23 are provided about midway across the width of cross braces 15a and 15c. The sides facing front legs 11a and 11c, respectively, of recesses 23 are coextensive with the inner edges thereof. 
     As shown in FIG. 11, seat supporting bars 21a and 21b each have therein a recess 22 to engage one of the recesses 23 in front cross braces 15a, 15c. This engagement keeps seat 20 from shifting horizontally. The use of L-section bars for seat supporting bars 21a, 21b results in the seating load being distributed uniformly among legs 11a, 11c and cross braces 15a, 15c. 
     FIG. 4 shows portion X1 of FIG. 3 on an enlarged scale, illustrating how the rear end of seat 20 is connected to rear legs 11b, 11d. In this respect, and as shown by FIGS. 11 and 12, supporting bars 21a, 21b have at the rear ends thereof tabs 24 with guide pins 26 projecting outwardly from their outer surface. 
     Tabs 24 are formed to be integral with seat supporting bars 21a, 21b. Seat supporting bars 21a, 21b have recesses 34a, 34b in the general area of tabs 24. For connecting seat 20 with rear legs 11b, 11d, cross braces 15b, 15d have recesses 25 at their top ends. As shown in FIGS. 4 and 13, guide pins 26 engage recesses 25 at tabs 24. 
     As shown in FIG. 13, the outwardly facing sides of recesses 25 are coextensive with the inner edges of rear leags 11b, 11d, with the exception of that portion of recess 25 through which guide pins 26 are passed. 
     As shown in FIG. 4, guide pins 26 include recesses 27 for each one of legs 11b and 11d. In the maximally spaced position of legs 11b, 11d, the portion of the recess through which guide pins 26 are passed overlies leg recesses 27. With seat 20 assembled to folding chair 10, guide pins 26 engage leg recesses 27, causing the seating load to be transmitted to rear legs 11b, 11d. 
     As shown in FIG. 9, back rest 14 has at its opposite ends enlarged portions 18 to prevent it from slipping from the clamping retention arragement. Back rest 14 comprises a back-rest web of fabric 30 having lateral pockets 36 at both ends thereof. Pockets 36 receive tubular sleeves 31 that form said enlarged portions 18. 
     FIG. 10 shows seat 20 to have two seat supporting bars 21a, 21b extending longitudinally along the sides thereof. Said laterally extending supporting bars 21a, 21b have a web of fabric 28 associated therewith to serve as a seat. 
     Seat web 28 has pockets 37 extending along the side edges thereof to removably receive supporting bars 21a, 21b. Portions 29 are cut from seat web 28 in positions where supporting bars 21a, 21b are to be connected to front legs 11a, 11c. Said portions 29 prevent damage to seat web 28 at the highly stressed points of connection. Seat web 28 does not extend to cover the rear portions of seat supporting bars 21a, 21b so as to reduce the load on rear legs 11b, 11d. 
     In an embodiment not shown, seat 20 is connected to legs 11a, 11b, 11c, 11d by articulation means. For example, rear ends of seat supporting bars 21a, 21b may be connected to rear legs 11b, 11d through rotary or pivoting joints, enabling seat 20 to be turned up or down as the chair is folded. 
     FIGS. 11 and 12 show the construction of seat supporting bar 21a, which is a mirror-image embodiment of seat supporting bar 21b. As described above, each seat supporting bar 21a, 21b has at the rear end thereof a projection or tab 24 holding a guide pin 26. Tabs 24 are integrally joined to seat supporting bars 21a, 21b and are delimited laterally by recesses 34a, 34b. Seat supporting bars 21a, 21b have recesses 22 therein, as shown in FIG. 11. As shown in FIG. 5, recesses 22 are adapted to be made to cooperate effectively with recesses 23 provided in front cross braces 15a, 15b. 
     Recesses 23 extend in the form of slots in a rearwardly inclined direction from the bottom lateral edge of seat supporting bars 21a or 21b. This orientation corresponds to angle α of front legs 11a, 11c, as shown in FIG. 1, to ensure a horizontal position of seat 20 in the inclined position of legs 11a, 11c. Supporting bars 21a, 21b are L-shaped in cross-section. Legs 11a, 11b, 11c and 11d consist of L-section bars, as do supporting bars 21a, 21b. 
     In the folded condition, there is formed--see FIG. 14--a square-section hollow tube 35 delimited by the L-section bars of long sides of legs 11a, 11b, 11c, 11d. This hollow space 35 will accommodate seat 20 and back-rest 14, which have been removed from th assembly before. This manner of stowing seat 20 and back-rest 14 allows chair 10 to be folded together into a compact and space saving square-section tube which is very easy to store. To provide a free inner space 35 as big as possible, cross braces 15a, 15b, 15c, 15d are formed of flat-section bar material.