CA1172775A

CA1172775A - Seat frame

Info

Publication number: CA1172775A
Application number: CA000404126A
Authority: CA
Inventors: Robert A. Snider
Original assignee: Individual
Current assignee: Individual
Priority date: 1981-06-01
Filing date: 1982-05-31
Publication date: 1984-08-14

Abstract

ABSTRACT OF THE DISCLOSURE
A one-piece seat frame structure having a plurality of parallel curvilinear slots which demarcate cantilever-action spring segments. A thin-walled, hollow, molded plastic body, or a similar body of another suitable rela-tively rigid material having resilient characteristics, has a pair of side walls, a rear wall, a front wall and a positively bowed top. A plurality of parallel curvilinear slots are provided through the top to demarcate a plurality of parallel curvilinear spring segments. In response to a typical load created by a seat occupant, the spring segments are deflected downward in a cantilever manner.

Description

~ ~72;77~ `

2 This invention relates to a one-piece seat frame

3 structure having a plurality of parallel curvilinear slots

4 which demarcate cantilever-action spring segment~.
Seat back assemblies,seat bottom assemblies, and 6 combination seat back-seat bottom assemblies which consist 7 essentially of a seat frame having a plurality of springs, 8 a cushion or pad which rests on the springs, and an up-9 holstery cover are well known in the seating and related arts. Such assemblies are widely used as components of 11 seats for auditoria, theaters, schools and similar public 12 buildings and as components of seats for buses, trains, 13 airplanes and other public transportation ~ehicles. Of 14 course, such assemblies are used as components o~ seats fox ma~y other public and private use environments.
16 For the majority of the seat assemblies of the type 17 described above, an open seat frame is manufactured from a 18 suitable structural material, often a wood framing or steel 19 sheet material, and conventional steel springs are positioned across one opening o~ the frame to support the weight of 21 the occupant of the seat. Typically, the steel springs are 22 of the coiled or serpentine type and are positioned parallel `23 to each other with the opposite ends of each secured to 24 the frame ky conventional means, such as engaging holes in the frame with hooks formed on the ends of the springs. Other 26 types of steel springs, such as either bowed or flat slats, 27 and springs fabricated from other materials, such as wood 28 or plastic, are occasionally used with such assemblies.
29 It is well known to those skilled in the seating and related arts that seat assemblies having a conventional 33l open seat frame with a pluralit~ of conventional springs ` ~7~

1 securcd thereto have many inherent disadvantages. For 2 example, conventional steel springs having suitable elastic 3 characteristics add substantially to the cost of manufac-4 turing such assemblies. Furthermore, pexiodic adjustment and repair is required to maintain the effectiveness of 6 conventional steel springs as flexible or resilient support 7 means. A thick cushion or pad is required to distribute 8 and transfer the seat occupant's weight to the springs and 9 to protect the seat occupant from possible bodily injury by contact with the springs. Upholstering is often a prob-11 lem when a conventional open seat frame having a plurality 12 of conventional sprin~s is utilized since the springs can 13 tear both the cushion or pad material and the upholstery 14 material.
Various structures have been proposed, and occasion-16 ally used, as alternatives for conventional open seat frames 17 having a pluralit~ of conventional springs. For example, 18 V.S. Patent No. 3,399,883, issued to McKey, for a "Seat 19 Construction", discloses a seat frame structure consisting essentially of a single sheet of resilient material which 21 functions as a flexible or resilient support means ~or a 22 seat assembly. Two rows of parallel tapered slots permit 23 the midportion of the sheet to assume the countour of the 24 load created by the seat occupant. A similar seat frame structure is disclosed in U.S. Patent No. 2,804,129, issued 26 to Propst, wherein a single seat of resilient material 27 is provided with parallel untaped slots around its periphery.
28 Each end of each such slot terminates in a circular recess.
29 Unfortunately, neither these structurcs, nor similar structures which are known in the seating and related arts, 31 have proved to be entirely satisfac-tory as fle~ible or 7~

l resilient support means for seat assemblies inasmuch as 2 they do not efficiently assume the contour of the load 3 created by the seat occupant.
4 It is desirable to have a one-piece seat frame structure which efficiently assumes the contour of the 6 load created by the seat occupant. Such a seat frame 7 structure, when used as a component of a seat assembly, 8 should be as comfortable for the seat occupant as a con-9 ventional open seat frame having a plurality of conventional springs. But, such a seat frame structure should not have ll the manufacturing cost and other disadvantages which are ~ ¦inherent i conventicnal structures.

~78 32 ~3-.

~2~

1 SUMMARY OF TH:E: INVENT:I:O~
2 The present invention provides a one-piece seat 3 frame structure which overcomes many of the inherent 4 disadvantages of conventional seat frames having a plur-

5 ality of conventional springs. The sea~ frame structure

6 of the present invention is relatively inexpensive to

7 manufacture. Yet, since it efficiently assumes the

8 contour of the load created by the seat occupant, a seat

9 assembly using the seat frame structure of the present

10 invention as a component is as comfortable for the occu-

11 pant as a conventional seat assembly.

12 The seat frame structure of the present invention

13 comprises an essentially rectangular, hollow body having

14 an open bottom and a positlvely bowed top. A plurality of

15 parallel curvilinear slots are provided through its top

16 to demarcate a plurality of parallel curvilinear spring

17 segments. In response to a typical load created by a seat 1~ occ~pant, the spring segments are deflected downward in a 19 cantilever manner. The radius of curvature of the slots and the distance bPtween adjacent slots can be varied to 21 control the configuration of the spring segments, and, 22 thereby, to control the degree of firmness of a seat 23 assembly incorporating the seat rame structure of the 24 present invention~

~7 3~ -4-~ ~7~7~

2 Figure 1 is a top plan view of a seat frame structure 3 embodying concepts of the present invention.
4 Figure 2 is an elevational view, in section, taken along line 2-2 in Figure 1.
6 Figure 3 is an elevational view taken along line 7 3-3 in Figure 1.
8 Figure 4 is an elevational view, in section, taken 9 along line 4-4 in Figure 1, but further illustrating a seat cushion and a seat cover fitted over the seat frame 11 structure and the cantilever-action spring segments of 12 the seat frame structure partially deflected in response 13 to a typical load created by a seat occupant.
14 Figure 5 is a side elevational view, in partial section, of an auditorium or theater seat illustrating 16 one use for the seat frame struct:ure of the present 17 invention.

18 Figure 6 is a side elevational view, in partial

19 section, of a chair or sofa illustrating another use for the seat frame structure of the present invention.
21 Figure 7 is a side elevational view, in partial 22 section, of a car or truck seat illustrating still another ~23 use for the seat frame structure of the present invention.

3~ -5-~727~5 1 DETAILED DESCRIPTION OF THE PREFERRED EMBODI.~NT
2 The preferred embodiment of the seat frame struc-3 ture of the present invention is illustrated in Figures 4 1-7. In its preferred embodiment, the seat frame struc-ture of,the present invention is used as a component of 6 a seat bottom assembly. However, seat frame structures 7 embodying concepts of the present invention can be fabri-8 cated for use as components of seat back assemblies and g combination seat back - seat bottom assemblies.
Referring to Figures 1-3, the seat frame structure 11 which is illustrated comprises a thin-walled, hollow, 12 molded plastic body 10 having a pair of essentially paral-13 lel side walls 12, a straight rear wall 14 and an out-14 wardly curved front wall 16, both perpendicular to said side-walls 12, and a top 18. A plurality of parallel 16 curvilinear slots 20 through the top 18 demarcate a plur-17 ality of parallel curvilinear spring segments 22. ~he 18 top 18 has a gentle upward slope from the side walls 19 12 which creates a slight positi~e bow for the spring segments 22. A plurality of short gussets or ribs 24 are 21 positioned in the interior void of the plastic body 10 22 to reinforce the structure at the intersections of the 23 side walls 12, the rear wall 14 and the front wall 16 24 with the top 18.
Referring to Figure 4, a seat cushion 26 formed 26 from a conventional foam rubber or another suitable resil-27 ient material rests on the top 18 of the plastic body 10.
28 Preferably, the seat cushion 26 is pre-molded or.formed 29 in place to fit snugly over and around the top 18, the side walls 12, the rear wall 14 and thefront wall 16 of 31 the plastic body 10. A seat cover 28 of conventional 1 upholstery material is fitted over the seat cushion 2 26 and secured to the lower edges of the side walls 3 12, the rear wall 14 and the front wall 16 with con-q ventional u-clips 30 or other conventional means.
Preferably, an indentation 32 is provided around said 6 lower edges to recess the u-clips 30.
7 Having described the seat frame structure of the 8 present invention, its use environment and performance 9 during use will now be described. In Figures 5-7, the seat frame structure of the present invention is shown 11 as a component of a seat bottom assembly for an audi-12 torium or theater seat 34, a chair or sofa 36, and a car 13 or truck seat 38, respectively. Returning to ~igure 4, 14 the response of the seat frame structure of the present invention to a typical load which is created by an occu-16 pant of one of the seats in Figures 5-7 is clearly illus-17 trated. As with conventional bowed slot springs, each 18 of the spring segments 22 has elastically deformed such 19 that its positive bow has beccme a negative bow. But, unlike conventional bowed spring slats, the elastic de-21 foxmation is not uniform along the width of each spring 2 segment 22. Rather, the leading edge of each spring 3 segment 22, i.e. khe edge nearest to the front wall 16 24 of the plastic body 10, is deflected downward in a manner similar to that of a conventional cantilever beam which 26 has a concentrated load applied to its free end.
Strictly speaking, the spring segments 32 do not 28 con~orm to the classical definition of a cantilever, i.e.
29 a beam or other member securely ~ixed at one end and hanging free at the other end. But, because of their 31 characteristic response to load described above, it is :~7~77~

1 believed to be not only helpful but also proper to 2 describe the spring segments 22 as cantilever-action spring 3 segments or cantilever-action springs. The use of 4 parallel curvilinear slots 20 to demarcate cantilever-action spring segments 22 in the top 18 of a molded 6 plastic body 10 has proved to be an e~ficient means for 7 economically constructing a one-piece seat frame structure 8 having suitable resiliency. Furthermore, the use of 9 such slots 20 permits the seat designer to achieve various degrees of resiliency, i.e. a relatively soft seat or a 11 relatively firm seat, by varying the radius of curvature 12 of the slots 20 and the distance between adjacent slots 20, 13 thereby controlling the contour and width of the cantilever-14 action spring se~ments 22.
While the preferred embodiment of the present in-16 vention has been described as a molded plastic body, it 17 should be understood that the present invention is not 18 limited by the materials or methods for fabrication of 19 the seat frame structure. Any relatively thin material which has suitable resilient characteristics and which 22 can be formed into a relatively rigid body is suitable 2 for fabrication of the seat frame structure of the present 3 invention. In like manner, any fabrication method which 24 is compatible with achieving the desired resiliency and rigidity characteristics for the material selected can be 26 used. Finally, it should be understood that there may 27 be other embodiments which fall within the spirit and 2B scope of the invention as defined by the claims~

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed-are defined as follows:-

1. A seat frame structure, comprising a relatively rigid, thin-walled, hollow body of material having resilient characteristics, said body having a pair of side walls, a rear wall, a front wall and a top with a plurality of para-llel curvilinear slots therethrough which demarcate a plural-ity of parallel curvilinear spring segments for downward deflection in a cantilever manner in response to a typical load created by a seat occupant.

2. A seat frame structure as recited in Claim 1, where-in said top is sloped upward from said side walls thereby creating a positive bow for said curvilinear spring segments.

3. A seat frame structure as recited in Claim 1, where-in said side walls are essentially parallel to each other and said rear wall and said front wall are essentially perpendicular to said side walls.

4. A seat frame structure as recited in Claim 3, where-in said top is sloped upward from said side walls thereby creating a positive bow for said curvilinear spring segments.

5. A seat frame structure as recited in Claim 1, 2, or 3, wherein said relatively rigid, thin-walled, hollow body of material having resilient characteristics is a molded plastic body.

6. A seat frame structure as recited in Claim 4, further comprising said relatively rigid, thin-walled, hollow body of material having resilient characteristics is a molded plastic body.

7. A seat frame structure as recited in Claim 1, 2 or 3, further comprising a plurality of short gussets or ribs positioned in the interior void of said relatively rigid, thin-walled, hollow body of material having resilient characteristics to reinforce the intersections of said side walls, said rear wall and said front wall with said top.

8. A seat frame structure as recited in Claim 4, further comprising a plurality of short gussets or ribs positioned in the interior void of said relatively rigid, thin-walled, hollow body of material having resilient characteristics to reinforce the intersections of said side walls, said rear wall and said front wall with said top.