Seating Structures With Flexible Backs

This invention relates to improved seating structures of a type having portions which are shiftable in certain respects in correspondence with the movements of a user's body, to enhance the user's comfort.

Most conventional types of seat backs with which we are familiar have a tendency to become very uncomfortable after a user has been in the seat for any substantial period of time. This is true even in the case of upholstered type seats, which though cushioned for the purpose of providing a soft and yielding support to the user's back, are not capable of giving as effective support as would be desired when the user shifts his body slightly to different positions over a period of time. Further, many of these prior seats are, in any body position, very uncomfortable to the spine, by reason of their construction in a manner causing exertion of a substantial portion of the back supporting force directly against the bones of the spine, or by reason of their construction in such a non-supportive manner as to allow the spine to overly relax in a curved condition and rapidly develop fatigue.

The present invention provides a unique seat back arrangement which includes two back elements positioned to support the back of the user along opposite sides of his spine, with these elements being carried by a common mounting structure connected to lower portions of the two elements and yieldingly mounting them for resiliently resisted rearward deflection relative to the mounting structure and relative to one another in correspondence with shifting movements of different portions of a user's body. These two elements are free of attachment to one another at their upper ends, and along inner edge portions of the two elements as those portions extend downwardly along the spine. These inner edge portions of the two elements are so shaped as to leave the user's spine itself essentially unsupported, so that the spine may project rearwardly slightly beyond adjacent portions of the user's back, and thereby avoid exertion of the above discussed unwanted forces directly against the spine. This result is preferably achieved by providing the seat back structure with a slit extending downwardly between the two back supporting elements, and dimensioned to receive the spine therebetween.

The seating device of the invention may be a portable unit which is positionable on an upholstered seat or chair, such as for example an automobile seat, in which event the mentioned mounting structure for the two elements may include an anchoring projection adapted to extend into a space between two cushions of the upholstered seat and retain the portable structure in a desired position relative thereto. Also, in certain instances the two back supporting elements or portions of the device may have cushioning sleeves received thereabout for further improving the comfort of the back support.

The lower position of the back structure may be connected to a seat proper, which projects forwardly and is desirable bifurcated to form two forwardly projecting halves which are relatively vertically deflectable to accomodate upward and downward movements of opposite sides of the user's body.

The above and other features and objects of the invention will be better understood from the following detailed description of the typical embodiments illustrated in the accompanying drawings, in which:

FIG. 1 is a perspective view of a seat device embodying the invention, shown positioned on an automobile seat;

FIG. 2 is a vertical section taken on line 2--2 of FIG. 1;

FIG. 3 is a front elevational view taken on line 3--3 of FIG. 2;

FIG. 4 is a vertical section taken on line 4--4 of FIG. 3;

FIG. 5 is a horizontal section taken on line 5--5 of FIG. 3;

FIG. 6 is a fragmentary plan view taken on line 6--6 of FIG. 2;

FIG. 7 is a view similar to FIG. 2, but showing a variational form of the invention;

FIG. 7a is a front elevational view of the FIG. 7 device;

FIG. 8 is a perspective view showing a further variational arrangement; and

FIG. 9 shows the FIG. 8 device as it is being folded to a more portable condition.

Referring first to FIG. 1, we have illustrated at 10 in those FIGURES a portable seating unit which is illustrated as applied to an upholstered seat 11. This seat 11 may typically be an automobile seat, having a generally horizontal seat cushion 12 and an upwardly projecting back cushion 13.

The unit 10 includes a preferably one piece body 14, which may be molded integrally from an appropriate resinous plastic material, and carry two cushion sleeves 15. the material of body 14 is essentially stiff to afford substantial support to the different portions of the user's body, but has some resilient deformability as will be brought out as the description progresses. This body forms an upwardly projecting back structure 16, a generally horizontal forwardly projecting seat structure 17, and a rearwardly extending anchoring projection 18 merging essentially with the juncture of the back 16 and seat 17. As seen best in FIG. 2, this anchoring projection initially extends downwardly at 19, and then curves rearwardly and ultimately upwardly to a location 20, to have an essentially hook-shaped vertical cross sectional configuration defining an upwardly facing or upwardly concave recess 21 within which the lower edge portion of upholstered seat cushion 13 is received to effectively retain unit 10 in the FIGS. 1 and 2 position relative to the upholstered seat. The projection 18 desirably has the cross section of FIG. 2 entirely across the width of that projection, transversely of the seat.

The seat back portion 16 of body 14 may be inclined slightly rearwardly as it extends upwardly along the front of the inclined forward surface 122 of the upholstered cushion 13. In extending upwardly, the seat back portion 16 has a first relatively narrow supporting post portion 22 which is symmetical with respect to a central vertical front to rear plane 23 of the seating device 10. At the upper end of post 22, the seat portion 16 of body 14 carries a portion 24 of a considerably increased width w, desirably at least several times the width l of post 22, with this upper wide portion of the body 14 containing a slit 25 extending downwardly from the top of body 14 to a location 26. Slit 25 is centered with respect to the previously mentioned vertical central front to rear plane 23, and is of a width t just great enough to easily accomodate the spine of a user in a relation avoiding direct exertion of supporting force against the spine. More particularly, the width t may be between about 1 and 2 inches.

The slit 25 thus divides the upper portion of the seat back structure into two halves 28 and 29, each of which is the mirror image of the other, and which are defined by lower generally horizontal edges 30, outer essentially vertical edges 31, upper essentially horizontal edges 32, and spaced parallel essentially vertical inner edges 27 of the two halves defining slit 25. Since the user's spine is intended to be located at essentially the vertical central plane 23, the two halves 28 and 29 of the upper portion of the back structure function essentially as two laterally spaced elements for engaging the user's back at opposite sides of the spine respectively, to support the back at those two locations somewhat independently and in a relation enabling accomodation of the back structure to changes in position of the user's body. The resinous plastic or other material from which the body 14 of the device is formed has sufficient resilient deformability to enable both of the seat back halves 28 and 29 to be bent rearwardly through a substantial distance by the user's body, either together as to the broken line positions represented at 28' and 29' in FIG. 5 (when the same force is exerted against both of the elements 28 and 29), or separately and relative to one another as represented by the position 128 of element 28 in FIG. 5 (greater force exerted against one of the elements 28 or 29 than the other). These different types of movement of the two halves 28 and 29 are rendered possible primarily by bending and/or twisting of the material of the seat back at its narrow mounting post portion 22 and/or at its narrow neck portions (dimension x in FIG. 3) which connect elements 28 and 29 to post 22 and to one another. At the same time, the stiffness of these portions of the back structure is sufficient to yieldingly resist deflection of each of the elements 28 and 29 with a substantial force giving a very effective resilient support to each side of the user's back. Preferably, the two halves or elements 28 and 29 have their lower edges 30 positioned at or just slightly above the level of a plane 33 (FIG. 3) which is at the user's waistline. As will be apparent from the drawings, the width dimention l of mounting post portion 22 of the device, and the widths x of the two connector portions which attach elements 28 and 29 to post 22, are all desirably several times as great as the minimum front to rear thicknesses of each of the portions 22, 28 and 29, as well as the minimum front to rear thicknesses at the locations of dimensions x.

The two cushion sleeves 15 may be formed essentially as inverted sacks, which can be removably slipped downwardly about the two halves 28 and 29 from a position such as that illustrated at 15' in FIG. 3. More particularly, each of these sleeves may be formed from two front and rear pieces of fabric stitched together along their upper edges 34, outer edges 35, and inner edges 36 down to a location 37, with the inner edges being open at 38 beneath the location 37, and with the bottom edges 39 also being open. Each cushion 15 may thus be slipped downwardly to a location at which the point 37 is just above the lower extremity 26 of slit 25. A layer of padding 39 is provided within each of the cushion sleeves, and is appropriately secured thereto, to be received at the front side of a corresponding one of the back supporting halves 28 or 29 to cushion the support afforded thereby. Alternatively, cushioning pads can of course be secured directly to the front of halves 28 and 29, as by means of velcro fasteners or the like.

As seen in FIGS. 4 and 5, the two back supporting halves or elements 28 and 29 may be contoured to effectively support the back of a user, preferably by curving the opposite side edge portions 41 slightly forwardly as seen in FIG. 5, and by curving the elements slightly rearwardly as they advance upwardly, as seen in FIG. 4.

The seat portion 17 of the device 10 is connected integrally at its back edge to the upstanding post portion 22 of the back structure, and projects forwardly along the top of seat cushion 12. Seat portion 17 is contoured to comfortably support a user's body, as by curving the rear edge of this seat portion upwardly at 43, and similarly curving the opposite side edges upwardly at 44. A slit 45 (FIG. 6), which is symmetrical with respect to the central vertical plane 23, divides the forward portion of the seat structure into two halves 46 and 47, which are mirror images of one another, and which support the two halves respectively of the user's body. These halves 46 and 47 are deflectable downwardly relative to one another, against the resilience of the material forming the seat.

When the seat device 10 is in use, whenever the user tends to become fatigued in one body position he unconsciously shifts his weight very slightly with respect to the seat device 10 to a more comfortable position, and in doing so may bend one of the seat back halves or elements 28 or 29 slightly rearwardly relative to the other element and relative to post 22 and seat 17, and may similarly deflect one of the halves 46 or 47 of the bifurcated seat 17 slightly downwardly relative to the other half, but with these movements being yieldingly resisted by the inherent resilience of the material of which body 14 is formed. Frequent relatively minute changes in position of this type keep the user comfortable over very long periods of time. Further, the support afforded to the back by elements 28 and 29 and their cushion sleeves 15 is at optimum support locations, just above the waistline and at opposite sides of the spine. The spine itself, just above the waistline location, is free to project slightly rearwardly into slit 25 between elements 28 and 29, that is, the spine may project rearwardly slightly beyond the laterally adjacent portions of the user's back which are supported by elements 28 and 29 along opposite sides of slit 25. In this way, the discomfort which results when the spine itself is directly supported against rearward movement is avoided.

FIGS. 7 and 7a are views similar to FIGS. 2 and 3 respectively, but showing a variational unit 10a which is identical to that of FIGS. 1 to 6 except that the seat portion 17 of the device has been omitted. This leaves only a back structure 16a corresponding to that illustrated at 16 in the first form of the invention, integrally carrying at its lower end an anchoring portion 18a at its lower end which may be wider than supporting post 22a as shown. Back structure 16a may or may not have two cushions 15a corresponding to those illustrated at 15 in FIG. 1. The device of FIGS. 7 and 7a may thus be applied to an automobile seat or other upholstered seat and be utilized for more effectively supporting the back of a user, and allowing frequent slight shifting movements of the back while at all times maintaining effective support thereof, with the device being held in place by the anchoring portion 18a positioned as illustrated in FIG. 2.

FIGS. 8 and 9 show another arrangement in which a back structure 16b identical with that described at 16 in FIGS. 1 to 6, and preferably carrying cushioning sleeves 15b on its two upper halves 28b and 29b, is connected at the lower end of its mounting post portion 22b (corresponding to portion 22 of FIGS. 1 to 6) to the rear edge of a seat assembly 48. This seat assembly 48 may be similar to the arrangement illustrated in U.S. Pat. No. 3,749,442, and more particularly may include a rigid horizontal base plate 49 which rests on a supporting upholstered cushion or other support, and which movably carries two generally horizontal seat sections 50 and 51 for engaging and supporting opposite sides of a user's body. These two sections 50 and 51 may be appropriately cushioned, and are connected at their undersides to base 49 by universal connections 52 which allow each of the sections 50 and 51 to have independent slight universal pivotal movement relative to base 49 for supporting the user's body in different positions. At its rear edge, base 49 of the seat assembly is connected to the lower portion of back structure 16b by a horizontal transverse hinge 53, which mounts the back for swinging movement forwardly from the position of FIG. 8 through the position of FIG. 9 to a position essentially overlying and parallel to seat assembly 48, in which folded condition the entire assembly is very easily portable. In its upstanding active position, the seat back 16b may be supported against further rearward swinging movement by engagement of post 22b with an upwardly extending rear flange portion 53 of base 49, which flange portion may contain a hand hole aperture 54 providing a handle by which the assembly in folded condition may be carried.

When this arrangement of FIGS. 8 and 9 is in use, the seat structure provides optimum vertical support to the user's body, with freedom for shifting movement to different positions, while the back structure 16b provides support to the user's back, again with freedom for shifting movement as discussed in connection with the first form of the present invention.

While certain specific embodiments of the present invention have been disclosed as typical, the invention is of course not limited to these particular forms, but rather is applicable broadly to all such variations as fall within the scope of the appended claims.