APPARATUS FOR SUPPORTING FLOOR BOARD OF EXTRENSIBLE STEPPED SEAT ASSEMBLY

Abstract: An apparatus for supporting a floor board of an extensible stepped seat assembly of the type in which a plurality of seat units are linked together in such a manner that when in use, underlying seat units are stepwisely extended in the forward direction, while when out of use, said underlying seat units thus extended forwardly are retracted and stored in the uppermost seat unit, wherein there is provided an elevating leg (15) which is designed so as to go down into abutment against the upper surface of an underlying seat unit (B) to support the load of the front end of the overlying seat unit (C) and there is also provided driving means (20) adapted to lower the elevating leg (15) in abutment against part of the underlying seat unit when the underlying seat unit is retracted and to raise the elevating leg (15) when the underlying seat unit (C) is stepped forward, thereby securely supporting the overlying seat (D) unit on the underlying seat unit (C) to prevent the swinging operation or rocking operation of the seat units and to prevent the front part of the floor board of each of all the seat units which are stored from being cantilevered and hanged down.

Description: BACKGROUND OF THE INVENTION The present invention relates to an apparatus according to the preamble of claim 1. Such apparatus, disclosed for instance in DE-A-3 013 529, provides for securely supporting a front part of a floor stand of each seat unit on a floor stand of an underlying seat unit so as not to be cantilevered in an extensible stepped seat assembly (hereinafter referred to as a seat), and is constructed such that when in use, individual seat units can be stepwisely extended, while when out of use, underlying seat units can be stored in the uppermost seat unit. Figure 4 schematically shows an example of a conventional seat of the above-mentioned type, in which (A), (B), (C), (D) and (E) are seat units, 1 is a truck, 2 is a strut, 3 is a floor board and 4 is a bench which is provided at the front end of the floor board. The seat of this type is constructed such that when it is fully extended, the rear ends of the floor boards 3 of the second and other succeeding seat units (B), (C), (D) and (E) are supported on the left and right struts 2 or on a supporting member (not shown) adapted to link the struts together and the front ends thereof are supported on the struts 2 of the seat units (A), (B), (C) and (D) which are respectively positioned directly under the seat units concerned. However, in a case that a small audience is occupied depending on the content of entertainments, it may sometimes happen that only the overlying seat units (C), (D) and (E) are extended to be used with the remaining underlying seat units (A) and (B) stored. In the above-mentioned case, in the conventional seat, there is a possibility that the front ends of the floor boards 3 of the seat units (B) and (C) are cantilevered and hanged down due to the absence of the struts 2 of the underlying seat units (A) and (B). And there is a danger that when many spectators move on the seat unit (C) in the above-mentioned cantilevered state, the floor board 3 of the seat unit (C) is inclined forwardly and downwardly and as a result of which the spectators fall from the seat unit (C) in the forward direction. In this connection, it is sometimes practiced that the both sides of the front end of the floor board 3 of each seat unit is supported on struts (not shown) erected on the truck 1 in order to avoid the cantilevered state of the front end of the floor board 3. However, even in the above-mentioned case, it is inevitable that the front end of the floor board 3 hangs down in the central portion thereof because the length of the floor board 3 is larger than the width. In order to avoid the above-mentioned danger, there has been proposed a structure as described in Japanese Utility Model Laid-Open Pub. No. 62-177845 which is constructed such that subsidiary spots are secured onto the front surfaces of the floor board of each seat unit which is still stored and of the floor board of a leading seat unit which has already been extended out to fixedly support the floor board of the leading seat unit. In addition, in Japanese Utility Model Laid-Open Pub. No. 62-54153, there is disclosed an arrangement that a plurality of seat units are moored together so as to move integrally in accordance with the content of entertainments. However, it takes much time and labor to attach and detach the subsidiary spots described in the above-mentioned Japanese Utility Model Laid-Open Pub. No. 62-177845 and its appearance is ugly. In addition, as described in the above-mentioned Japanese Utility Model Laid-Open Pub. No. 62-54153, in a case that the subsidiary spots as described above are used in a structure in which the number of the seat units which are moored integrally can be selected in accordance with the content of entertainments, such a problem associates that it is necessary to prepare a number of subsidiary spots of different height depending on the number of seat units to be moored. Accordingly, an object of the present invention is to solve the above-mentioned problems associated with the prior art. SUMMARY OF THE INVENTION The present invention has solved the above-mentioned problems with the provision of an apparatus in which there is elevatingly provided, in front of the lower surface of an overlying seat unit of a pair of seat units which are adjacent in vertical relation, an elevating leg which is designed so as to go down into abutment against the upper surface of an underlying seat unit to support the load of the front end of the overlying seat unit and there is also provided, in an appropriate position of the lower surface of the overlying seat unit, driving means adapted to lower the elevating leg in abutment against part of the underlying seat unit when the underlying seat unit is retracted and to raise the elevating leg when the underlying seat unit is stepped forward. In the apparatus according to the present invention, the essential front part of the lower surface of each seat which is stored is always put on and supported on the front part of the upper surface of a seat unit which is situated directly under the seat unit concerned automatically In accordance with the movement of an elevating leg, so that even when only overlying seat units are extended and used, a leading seat unit is securely supported on a seat unit directly under the leading seat unit and hence the leading seat unit never rocks even when the audience moves thereon. An optional development of the invention is given in claim 2. BRIEF DESCRIPTION OF DRAWINGS Other objects and advantages of the present invention will become apparent as the following specification progresses with reference to the accompanying drawings for illustrations of the prior art and of the present invention. In the drawings: Fig. 1 is an enlarged side view of an essential part of a seat to which the present invention is applied, in which struts are omitted; Fig. 2 is an enlarged central longitudinal side view of an apparatus according to the present invention; Fig. 3 is a sectional view taken along the line X-X of Fig. 2; and Fig. 4 is a schematic side view of a conventional seat arrangement. DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION The preferred embodiment of the present invention will be described with reference to the accompanying drawings. Fig. 1 shows an essential part of a seat to which the present invention is applied, in which the essential part is shown in the same manner as what is shown in Fig. 4 and a strut 2 is omitted. It is to be noted that the like numerals are assigned to like parts shown in Fig. 4 and the description thereof is omitted. As shown in Fig. 1, a supporter 11 which is inverted-U-shaped in the configuration of the front surface is fixed to an essential front part of the lower surface of a floor board 3 of each of seat units except the lowermost one, such as the seat unit (D), so as to orient in a transverse direction. Inclined holes 12 directing rearwardly and downwardly are pierced in both side strips 11a and 11a of the supporter 11. A guide strip 13 which directs rearwardly and is bent downwardly at the rear end thereof is coupled to the rear end of the upper surface of the supporter 11 and a guide hole 14 is formed in the guide strip 13. A square-boxed elevating leg 15 is fitted in the supporter 11. An engagement pin 16 which is transversly provided through the elevating leg 15 is fitted in the inclined holes 12 at the both ends thereof and the lower end of the elevating leg 15 is normally projected downwardly from the supporter 11. A coupler 17 which is of a rear-faced U configuration in the plane surface thereof is fixed to the rear surface of the elevating leg 15 and elongated holes 18 are symmetrically pierced in both-sided strips 17a thereof. A driving shaft 20 which is oriented in a transverse direction is supported in the guide hole 14 in the guide strip 13 and on a support strip 19 which is hangingly provided on a rear part of the lower surface of the floor board 3 so as to be movable in the fore and aft directions. A transversely oriented engagement pin 21 which is fixed to the front end of the driving shaft 20 is fitted into the elongated hole 18 in the coupler 17 and a driving plate 22 which is hangingly provided on the rear end thereof hangs down from the upper end of a supporting member 23 at the rear end of the floor board 3 of a seat unit, such as (C), which is situated directly under the seat unit concerned and is actuated in a forward direction by a compression spring 24 which is coiled up between the engagement pin 21 and the lower end of the guide strip 13. Accordingly, as shown by the seat units (C) and (D) in Fig. 1, in the extended state, the driving shaft 20 of the seat unit (D) is actuated by the spring 24 to the foremost position thereof, by which the elevating leg 15 which is situated in the upper foremost position thereof is put on the supporting member 21 of the seat unit (C) to avoid the swinging of the seat unit (D). Though not shown, when an underlying seat unit is retracted to be stored, the rear end of the floor board 3 thereof comes into abutment against the driving plate 22 of an overlying seat unit. Then, when the seat units are stacked up vertically as shown by the seat units (B) and (C) in Fig. 1, the driving shaft 20 of the seat unit (C) is retracted to its rearmost position against the spring 24, by which the elevating leg 15 which is lowered to its lowermost position comes into abutment against the bench 4 of the seat unit (B) to avoid the swinging of the seat unit (C). The above description concerns the operation of the seat units (B), (C) and (D). All the seat units (A) to (E) operate in a similar manner. In this connection, it is to be noted that although in the above-mentioned embodiment the driving shaft 20 and the compression spring 24 constitute driving means for raising and lowering the elevating legs 15 in accordance with the advancement and retraction of the underlying seat units (B), (C) and (D), the driving means may be replaced by an arrangement in which a wire is used instead of the driving shaft 20 or by an arrangement in which a gear is rotated in accordance with the advancement or retraction of the underlying seat unit to raise or lower the elevating leg. As has been described above, according to the present invention, the front essential part of the lower surface of each seat unit which is stored is always put on and supported on the front part of the upper surface of the seat unit which is situated directly under the seat unit concerned automatically in accordance with the movement of the elevating leg. Accordingly, with the employment of the appropriate number of the apparatuses according to the present invention corresponding to the lateral length of each seat unit, even when the upper stages of the seat are extended to be used by a desired number, a leading seat unit is securely supported on a seat unit which is situated directly under the leading seat unit and hence never swings or rocks due to the movement of audience or the like. Further, the present invention can prevent the front part of the floor board of each of all the seat units which are stored from being cantilevered and hanged down.

Claims: An apparatus for supporting a floor board (3) of an extensible stepped seat assembly of the type in which a plurality of front-faced gate type seat units (A, B, C, D, E) of different width and height in each of which struts (2) are erected on a pair of left and right trucks (1) running in forward and rearward directions are linked together in such a manner that when in use, underlying seat units (A, B, C, D) are stepwisely extended in the forward direction, while when out of use, said underlying seat units (A, B, C, D) thus extended forwardly are retracted and stored in the uppermost biggest seat unit (E), characterized in that in front of the lower surface of an overlying seat unit of a pair of seat units which are adjacent in vertical relation, there is elevatingly provided an elevating leg (15) which is designed so as to go down into abutment against the upper surface of an underlying seat unit to support the load of the front end of the overlying seat unit and there is also provided in an appropriate position of the lower surface of the overlying seat unit driving means adapted to lower the elevating leg (15) in abutment against part of the underlying seat unit when the underlying seat unit is retracted and to raise the elevating leg (15) when the underlying seat unit is stepped forward. An apparatus for supporting a floor board (3) of an extensible stepped seat assembly as defined in claim 1 wherein said elevating leg (15) is mounted so as to slide along downwardly inclined holes (12) which are formed in both sided strips (17a) of a supporter (11) which is fixed to the lower surface of the overlying seat unit and said driving means includes a driving shaft (20) which is linked to the elevating leg (15) at the front end thereof and is provided at the rear end thereof with a driving plate (22) which is moved rearward in abutment against the rear end of the underlying seat unit when said underlying seat unit is retracted said driving shaft (20) being oriented in a transverse direction, and a spring (24) adapted to normally actuate the elevating leg (15) in the forward direction.

Inventors: ANDO, KENJI
Applicants: OKAMURA CORPORATION
Application year: 1989
Main classification: E04H3
IPC codes: A47C1, E04H3