The object of the invention is to provide a transportable and light chair, particularly for use at festivals, rock concerts, as garden furniture as well as a common supple- ment to furniture in the home.

Thus, the collapsible seat with a back is to be offered for sale in the collapsible and thus easily transportable state. Furthermore, as mentioned it is to be in the form of only one product unit which is very easily unfoldable into a very comfortable and strong chair.

Background Art French patent specification No 2, 798, 049 Al discloses an unfoldable chair made from a light sheet material, particularly paper board or cardboard. However, the chair herein disclosed is not in the form of only one product unit, it is not very com- fortable to sit in and due to the structure thereof it is not very strong.

Disclosure bflnventibir Thus, the object of the invention is to provide a collapsible seat having a back rest and being unfoldable into a chair made from cardboard, paper board, plastics or plywood and being in the form of a single product unit in which every unfoldable panel section extends from the upper edge of a base structure. The structure in ques- tion must be capable of carrying a person of at least 150 kg and of forming a com- fortable seat with a back.

The object of the invention is obtained by the collapsible seat with a back rest being shaped as stated in the characterising part of claim 1.

As a result, a seat with a back rest is obtained forming a self-reinforcing and locked connection in the load direction of the seat and the back rest.

The preferred embodiments appear from the sub-claims.

Brief Description of the Drawings The invention is explained in detail below with reference to the drawings showing four embodiments of the invention and in which Fig. 1 shows a sheet-formed blank for producing a first embodiment of the collapsi- ble seat having a back rest according to the invention, Fig. 2 is a perspective view of the ready-made collapsible seat having a back rest, Figs. 3 to 5 successively show an unfolding into a chair of the collapsible seat hav- ing a back rest, Fig. 6 shows a second sheet-formed blank for producing a second embodiment of the collapsible seat having a back rest according to the invention, Fig. 7 is a perspective view of the second embodiment of the ready-made collapsible seat having a back rest, and Figs. 8 to 10 successively show the unfolding into a chair of the second embodiment of the collapsible chair having a back rest,

Fig. 11 shows a third sheet-formed blank for producing a third embodiment of the collapsible seat having a back rest according to the invention, Fig. 12 is a perspective view of the ready-made collapsible seat having the back rest of Fig. 11, and Figs. 13 to 15 successively show an unfolding into a chair of the third embodiment of the collapsible chair having a back rest, Fig. 16 shows a fourth sheet-formed blank for producing a fourth embodiment of the collapsible seat having a back rest according to the invention, Fig. 17 is a perspective view of the fourth embodiment of the ready-made collapsi- ble seat having a back rest, and Figs. 18 to 20 successively show an unfolding into a chair of the fourth embodiment of the collapsible chair having a back rest.

Best Modes for Carrying out the Invention Fig. 1 shows a sheet-formed blank 31 for producing a first embodiment of the col- lapsible seat having a back rest according to the invention. The unfolding of the col- lapsible seat having a back rest results in a chair. The sheet-formed blank 31 of Fig.

1, as viewed in the direction towards Fig. 1, shows the face of the sheet-formed blank 31, i. e. the back face, facing the inner side of the chair. The opposite face of the sheet-formed blank 31, i. e. the back face of the paper, is referred to as the front face of the blank. The sheet-formed blank 31 is punched as shown in Fig. 1 and in- cludes a number of sections designated the reference numerals indicated in the Fig- ure. In addition, the sheet-formed blank is provided with a number of fold lines indi- cated by dotted lines. Of the sections indicated, the sections 1, 2,3 and 4 are folding flaps folded during the manufacture around their fold lines 30,26, 27 and 28, re-

spectively, in such a direction that at the folding flaps 1,2, 3 and 4 the front face of the of the sheet-formed blank 31 is positioned on top of the back face of the sheet- formed blank 31 shown in Fig. 1. Then, the front face of the folding flaps 1,2, 3 and 4 is applied with an adhesive. The sheet-formed blank 31 is then folded around a fold line 29 in such a direction that the back faces of the two members shown in Fig.

1 abut each other. During this procedure, the front face of the folding flap 1 applied with an adhesive abuts and adheres to the back face of the blank along the edge 1 a in such a manner that the fold line 30 coincides with the edge la. In addition, the fold- ing flap 2 abuts and adheres to the back face of the blank along the edge 2a in such a manner that the fold line 26 coincides with the edge 2a. Furthermore, the front face of the folding flap 3 applied with an adhesive abuts and adheres to the edge 3 a of the blank in such a manner that the folding flap 27 coincides with the edge 3a. Finally, the front face of the folding flap 4 applied with an adhesive abuts and adheres to the back face along the edge 4a in such a manner that the fold line 28 coincides with the edge 4a. In this way, the collapsible seat having a back rest is ready-made in the shape seen in the perspective view in Fig. 2. It is noted that the sections 22 and 23 are provided with punched openings 22a and 23a, respectively, which serve as han- dles during transport of the collapsible seat in the completely collapsible state.

Fig. 2 shows the collapsible seat having a back rest in a slightly opened position, even though it can, of course, be collapsed completely into a position in which the sections are pressed tightly against each other such that for instance the sections 20 and 21 abut each other, the sections 22 and 23 abut each other and the sections 24 and 25 abut each other.

The collapsible seat having a back rest is usually sold in this completely collapsed state in which it can optionally be provided with a small label with guidelines for the buyer illustrating how the collapsible seat having a back rest can be unfolded to form a strong chair. This unfolding is shown successively in the following Figures, i. e. Fig. 3, Fig. 4 and Fig. 5. In the collapsible state, the upper portion of the blank is the edge la coinciding with the fold line 30. When unfolding the collapsible seat

into a chair, the hexagonal shape thereof should first be unfolded by pressing the fold line 26 in the direction towards the fold line 29. During the latter unfolding, the section 9 is pushed into the chair to form the seat of said chair. During this proce- dure, care should be taken that the sections 5 and 5a are guided behind the section 6 forming the back rest of the chair while ensuring that the sections 15 and 16 glued together along the edge 4a and the sections 15a and 16a glued together along the edge 3a are guided in front of the back rest of the chair approximately opposite the adhesion position at the edge la between the sections 7 and 8. As a result, all the sections 6,7 and 8 form the back of the chair while the section 9 as mentioned forms the seat of the chair. While the sections 5 and 5a are guided behind the section 6 as mentioned above, the small triangular sections 14,14a connecting the sections 5 and 6 and 5a and 6, respectively, to the fold lines 17,17a and 18,18a, respectively, are also guided behind the section 6 by a folding around the fold lines 17,17a and the fold lines 18,18a, respectively. As a result, the front face of the sections 14 and 5 of the blank and the front face of the sections 14a and 5a, respectively, of the blank abut each other which results in a considerable reinforcement of the upper corners of the chair.

The completely unfolded chair appears from Fig. 5. As mentioned, it is hexagonal and includes the sections 24,22, 21,20, 23 and 25, the lower edges thereof jointly forming a hexagonal basic form 13 optionally provided with folding flaps not shown below the chair to avoid the penetration of water from the base. Alternatively, the basic form 13 can preferably be provided with a waterproof cover on the edge rest- ing on the base and correspondingly preventing the penetration of water from said base.

Fig. 6 shows a sheet-formed blank 41 for producing a second embodiment of the collapsible seat having a back rest according to the invention. The unfolding of the collapsible seat having a back rest results in a chair of a pentagonal basic form 13a with an armrest corresponding to the armrests on the chair of Fig. 5, but only in the right side. In this way, the unfolded chair can be modularly placed side by side with

a corresponding chair with an armrest in the opposite side so as to form a two- person couch. In addition, according to the third embodiment, the above chair can be modularly placed side by side with corresponding chairs entirely without armrests, cf. the description of the following Figs. 11 to 15. As in Fig. 1, Fig. 6 shows the face of the sheet-formed blank 41, i. e. the back face, facing the inner side of the chair.

The opposite face of the sheet-formed blank 41, i. e. the back face of the sheet, is re- ferred to as the front face of the blank as stated above. The sheet-formed blank 41 is punched as shown in Fig. 6 and includes a number of sections designated the refer- ence numerals indicated in the Figure. In addition, the sheet-formed blank is pro- vided with a number of fold lines indicated by dotted lines. Of the sections indi- cated, the sections 1,2 and 3 are folding flaps folded during the manufacture around their fold lines 30,26 and 27, respectively, in such a direction that at the folding flaps 1,2 and 3, the front face of the sheet-formed blank 31 is positioned on top of the back face of the sheet-formed blank 41 shown in the Figure. Then, the front face in question of the folding flaps 1,2 and 3 is applied with an adhesive. The sheet- formed blank 41 is then folded around a fold line 42 in such a direction that the back faces of the two members shown in Fig. 6 abut each other. During this procedure, the front face of the folding flap 1 applied with an adhesive abuts and adheres to the back face of the blank along the edge la in such a manner that the fold line 30 coin- cides with the edge la. In addition, the folding flap 2 now abuts and adheres to the back face of the blank 41 along the edge 2a in such a manner that the fold line 26 coincides with the edge 2a. Furthermore, the front face of the folding flap 3 applied with an adhesive abuts and adheres to the edge of the blank in such a manner that the folding flap 27'coihcides with the edge 3a. In this way, the second embodiment of the collapsible seat having a back rest is manufactured in the shape shown in the perspective view of Fig. 7. The sections corresponding to the sections of the first embodiment are designated the same reference numerals. The same applies to he openings 22a and 23a serving as handles during transport of the collapsible seat in the completely collapsed state.

Unlike the first embodiment, some folding flaps 43,44 and 45 are provided in con- nection with the sections 9 and 8 and 7,6, respectively. In connection with the sec- tion 21, a closing folding flap 46 is provided and in connection with the section 20, two locking folding flaps 47 and 48 are provided. Fig. 7 shows the collapsible seat having a back rest in a slightly opened position, even though it can, of course, be collapsed completely into a position in which the sections are pressed tightly against each other so that for instance the sections 20 and 21 abut each other, the sections 22 and 23 abut each other and the sections 24 and 25 abut each other.

The collapsible seat having a back rest is usually sold in this completely collapsed state in the same way as in the first embodiment. The buyer can then unfold the col- lapsible seat having a back rest thereby forming a chair with an armrest positioned in the right side in the same way as in the first embodiment. This unfolding is shown successively in the following Figures, i. e. Fig. 8, Fig. 9 and Fig. 10. When unfolding the collapsible seat into a chair of a pentagonal basic form 13a, the basic form thereof must first be unfolded by pressing the fold line in the direction towards the fold line 42. During this procedure, the sections 20 and 21 are positioned on the same level. Then, the locking folding flap 46 is inserted as shown in Figs. 9 and 10 into a slit 43a in the fold line between the section 9 and the locking folding flap 43.

Moreover, the locking folding flap 47 is inserted into a slit 44a in the fold line be- tween the section 8 and the folding section 44; and the locking folding flap 48 is in- serted into a slit 45a in the fold line between the section 7 and the folding flap 45.

Accordingly, the chair appears as shown in Fig. 10 with an armrest positioned in the right side and without an armrest in the left-side-when seen according to a front view.

Fig. 11 shows a sheet-formed blank 51 for producing a third embodiment of the col- lapsible chair having a back rest according to the invention. The unfolding of the collapsible seat having a back rest results in a chair of a square, rectangular basic form 13b with a back rest, but without armrests or side members so that it is possible to modularly place several chairs of this type next to the chair shown in Figs. 6 to 10

at the one end and optionally a corresponding, but relative to Fig. 10, laterally re- versed chair with an armrest to the opposite side. As a result, the modularly joined chairs form a couch. The sheet-formed blank 51 of Fig. 11, as viewed in the direc- tion towards Fig. 11, shows the face of the sheet-formed blank 51, i. e. the back face, facing the inner side of the chair. The opposite face of the sheet-formed blank 51, i. e. the back face of the paper, is, as previously, referred to as the front face of the blank. The sheet-formed blank 51 is punched as shown in Fig. 11 and includes a number of sections designated the reference numerals indicated in the Figure. In ad- dition, the sheet-formed blank is provided with a number of fold lines indicated by dotted lines. Of the sections indicated, the sections 1 and 2 are folding flaps folded during the manufacture around their fold lines 26 and 30, respectively, in such a di- rection that at the folding flaps 1 and 2, the front face of the sheet-formed blank 51 is positioned on top of the back face of the sheet-formed blank 51 shown in Fig. 11.

Then, the front face of the folding flaps 1 and 2 is applied with an adhesive. The sheet-formed blank 51 is then folded around a fold line 52 in such a direction that the back faces of the two members shown in Fig. 11 abut each other. As a result, the front face of the folding flap 1 applied with an adhesive abuts and adheres to the back face of the blank along the edge la in such a manner that the fold line 30 coin- cides with the edge la. In addition, the folding flap 2 abuts and adheres to the back face of the blank 51 along the edge 2a in such a manner that the fold line 26 coin- cides with the edge 2a. In this way, the third embodiment of the collapsible seat hav- ing a back rest is manufactured in the shape shown in a perspective view in Fig. 12.

Fig. 12 shows the-collapsible seat having a back rest in a slightly opened position, even though it can, of course, be collapsed completely into a position in which the sections are pressed tightly against each other such that for instance the sections 20 and 21 abut each other, the sections 22 and 23 abut each other and the sections 24 and 25 abut each other.

The collapsible seat having a back rest is usually sold in this completely collapsed state from which it can be unfolded to form a chair. This unfolding is shown succes-

sively in the following Figures, i. e. Fig. 13, Fig. 14 and Fig. 15. In the collapsed state, the upper portion of the blank is the edge la coinciding with the fold line 30.

When unfolding the collapsible seat into a chair, the basic form, viz. rectangular here, thereof must first be unfolded by pressing the fold line 26 in the direction to- wards the fold line 52. During this procedure, the section 9 is pushed into the chair to form the seat of the chair. The section 7 is provided with the folding flaps 55 and 59 as shown in Fig. 11 with the indicated notches 55a and 59a. The section 9 is pro- vided with the indicated folding flaps 53 and 63 with the indicated notches 53a and 63a ; and the section 8 is provided with the indicated folding flaps 54 and 64 with the respective notches 54a and 64a. In addition, the sections 21 and 24 are provided with respective locking folding flaps 56 and 66; and the sections 20 and 25 are provided with the respective locking folding flaps 57,58 and 67,68. As shown in the Figures, particularly Figs. 13 and 14, the locking folding flap 56 is inserted into the notch 53a in the fold line between the section 9 and the folding flap 53; and the locking folding flap 67 is inserted into the notch 64a in the fold line between the section 9 and the folding flap 64. In addition, the locking folding flap 68 is inserted into the notch 59a between the section 7 and the folding flap 59. The locking folding flap 66 is inserted into the notch 63a in the fold line between the section 9 and the section 63, and the locking folding flap 57 is inserted into the notch 54a in the fold line between the sec- tion 8 and the section 54. Finally, the locking folding flap 58 is inserted into the notch 55a in the fold line between the section 7 and the folding flap 55. As a result, the chair appears as shown in Fig. 10 with a rectangular basic form and completely without arm rests.

Fig. 16 shows a sheet-formed blank 71 for producing a fourth embodiment of the collapsible chair having a back rest according to the invention. The unfolding of the collapsible seat having a back rest results in a chair of a rectangular basic form 13c with armrests. The entire upper portion, i. e. the portions forming the seat, the back rest and the armrests, are identical with the corresponding sections and portions in the first embodiment and are therefore not described in greater detail here. In other words, the manufacture of the collapsible seat having a back rest is completely simi-

lar to the manufacture of the first embodiment. However, instead of the vertical fold lines extending to the basic form of the chair, inclining fold lines are shaped as shown and form the triangular sections 73 to 86.

Fig. 17 is a perspective view of the ready-made collapsible seat having a back rest according to the invention in the almost completely collapsed state. The unfolding of this sheet-formed blank 71 is carried out in the same way as in the first embodiment by pressing the fold line 26 in the direction towards the fold line 9. During this pro- cedure, the section 9 is pushed into the chair to form the seat of the chair and the remaining unfolding actions shown in connection with the first embodiment are car- ried out in a corresponding way. This is shown successively in Figs. 18,19 and 20.

Due to the previously mentioned triangular sections, this unfolding procedure results in the hexagonal basic form 13c being turned 30° relative to the basic form 13 of the first embodiment provided that the seat, the back rest and the armrest of the chair of the first and fourth embodiments assume corresponding directions. Owing to this structure, the chair achieves a particularly strong carrying capacity.