Reinforcing Structure For Bodies With Curved Load-supporting Surfaces

Abstract

A tensionable internal reinforcing structure for a mattress, seat cushion or the like, comprising one or more elongate tension members each traversing a column of mutually abutting pressure elements to form a collapsible armature, includes several wedge pieces which are inserted between adjoining pressure elements to impart a desired curvature to the armature. The wedge pieces may be in the form of longitudinally slitted sleeves which are clipped either directly onto a tension member or onto a pressure element, being provided in the latter case with triangularly profiled end flanges to separate the engaged pressure element from its neighbors on one side of the centerline of the column. Aligned wedge pieces of adjoining armatures may be interconnected by a transverse strap.

Description

My present invention relates to a reinforcing structure for seats, mattresses and other load-supporting structures whose effective resiliency is to be adjusted from time to time to compensate for fatiguing of materials or to accommodate different loads or load distributions, as described in my prior U.S. Pat. No.3,490,084.

Such a reinforcing structure, as disclosed in that patent, includes one or more collapsible armatures each comprising a cable or similar elongate tension member which traverses a multiplicity of juxtaposed and mutually abutting pressure elements of generally tubular shape forming a column therearound. When the tension member is stressed against the column, the latter is rigidified so as to resist flexing; with the ends of these pressure elements slightly beveled, the column can be given a camber conforming, for example, to the convexity of an overlying seating surface. A number of such collapsible armatures, parallel or intersecting, can be assembled into a variety of arrays.

It is sometimes desirable, e.g., for the purpose of strengthening an aging structure, to camber an originally straight armature so as to increase its bending resistance under load. Such subsequent cambering, or the imparting of any other curvature to an already assembled column, has heretofore been possible only by disassembling the structure and replacing some or all of the straight-faced pressure elements with beveled elements of generally trapezoidal axial cross-section. This work of disassembly and subsequent reassembly is, of course, cumbersome and frequently not worth the effort.

The general object of my present invention, therefore, is to provide an improved reinforcing structure of the type disclosed in my above-identified patent in which the curvature of any armature may be modified merely upon a slackening thereof, thus without disassembly, to bend or to straighten its column to any desired extent within wide limits.

Another object of my invention is to provide means in such a structure for positively maintaining the orientation of a curved armature with reference to the load-supporting body to which it is anchored.

According to an important feature of my invention, I provide one or more wedge pieces adapted to be detachably inserted between any two pressure elements of a column in the slackened state of the armature for imparting curvature thereto in its rigidified state. Such a wedge piece may be a longitudinally slitted sleeve which should be sufficiently resilient to be clipped either onto the central tension member (possibly with interposition of a coil spring or a helically wound wire surrounding that member) or onto one of the pressure elements originally in the column. In the first instance, the sleeve may be simply inserted between two pressure elements, e.g., after removal of a third pressure element which originally separated these two elements and which may also be slitted longitudinally to facilitate such removal. In the second instance, the sleeve may be formed with at least one segmental end flange unilaterally projecting between the engaged pressure element and an adjoining element for partly separating same from each other, the imparted curvature thus depending upon the wedging effect of this flange.

An adjustable wedging effect may be realized by the use of a wedge piece of generally trapezoidal axial cross-section, permanently installed or laterally insertable as described above, with a tapering layer of elastically compressible material adhering to either or both of its end faces, this layer being subjected to adjustable pressure by an extension of the sleeve hingedly connected therewith at the corresponding end face.

The wedge piece, whether laterally removable or not, should be secured against rotation relative to the remainder of the column in order to preserve the desired direction of curvature. For this purpose, according to a further feature of my invention, I provide each of these wedge pieces with individual retaining means for holding them against rotation relative to the associated load-supporting body. Such retaining means may comprise, particularly in the case of a slitted sleeve, a clamp embracing that sleeve and overlying its axis slot, the sleeve being preferably urged into firm contact with the surrounding clamp by the aforementioned coil spring wound about the inner tension member. Such a clamp may be simply a ring with external ribs or the like taking hold on the surrounding body material; it could also be joined to a strap tied in similar manner to a like wedge piece of an adjoining second armature.

The above and other features of my invention will be described in detail hereinafter with reference to the accompanying drawing in which:

FIG. 1 is a fragmentary plan view (similar to FIG. 14 of my above-identified prior patent) of a reinforcing structure embodying my present improvement, with parts broken away;

FIG. 2 is a partial side view (also with parts broken away) of the structure of FIG. 1, taken on the line II--II thereof;

FIG. 3 is a sectional elevational view, drawn to a larger scale, of part of another embodiment;

FIG. 4 is a perspective view of a chair with a backrest incorporating a structure according to the invention;

FIG. 5 is a perspective view of part of a hospital bed with a back support incorporating a structure according to the invention;

FIG. 6 is a set of simplified perspective views of such a reinforcing structure in three different positions of adjustment;

FIG. 7 is an end view of a wedge piece shown adjacent a tension member of an armature according to the invention;

FIG. 8 is a side view of the wedge piece of FIG. 7;

FIG. 9 is a view similar to FIG. 3, illustrating another modification;

FIG. 10 is a perspective view of an element of the assembly of FIG. 9;

FIG. 11 is a side view of another modified wedge piece according to the invention;

FIG. 12 is a view similar to FIG. 11, showing the wedge piece thereof in a compressed state;

FIG. 13 is an end view of the wedge piece shown in FIGS. 11 and 12;

FIG. 14 is a view similar to FIG. 12, illustrating a further variant of the wedge piece;

FIG. 15 is an end view of the wedge piece of FIG. 14;

FIG. 16 is a cross-sectional view taken on the line XVI -- XVI of FIG. 2; and

FIG. 17 is a cross-sectional view taken on the line XVII -- XVII of FIG. 3.

In FIGS. 1, 2 and 16 I have shown a representative portion of a reinforcing structure including a pair of parallel armatures 10, 10' disposed in or next to a mattress, seat cushion or similar load-supporting body not shown in these Figures, e.g., a backrest 79 of a chair 80 (FIG. 4) or a back support 82 on a mattress 82a (FIG. 5). Each armature 10, 10' comprises a tension member in the form of a cable 8, 8' surrounded by a coil spring 65; the cable and the coil spring are threaded through a column of mutually abutting tubular pressure elements 7, 7' of any compression-resisting material. Cables 8 and 8' are anchored by means of terminals 9, 9' to a transverse bar 54 which, together with a similar bar 55, flanks a third bar 53 articulated to these outer bars by respective pairs of links 56, 56'. The columns of pressure elements 7, 7' bear at one end upon the bar 55 and are secured at the opposite end, not shown, to the respective cables 8, 8'. The bars 54, 55 are shiftable with reference to bar 53 by the hollow stem 58 of a knob, such as that shown at 81 in FIG. 4, which is journaled in a collar 59 and threadely engages a bolt 57 rigid with bar 53. With collar 59 hingedly connected to bars 54, 55 by means of links 51 and 52, rotation of stem 58 in one sense or the other will shift the center bar 53 in either direction (arrow A) with reference to the outer bars 54, 55 whereby the relative spacing of bars 54 and 55 is altered through the links 56, 56' with corresponding change in the tension of cables 8 and 8'. Thus, a relative shift of bar 53 to the left in FIG. 1 slackens the cables whereas a rightward shift stresses them to stiffen the columns.

In accordance with this invention, at least one of the pressure elements 7, 7' of each column 10, 10' is replaced by an equally pressure-resistant wedge piece 61, 61' with beveled end faces as best seen in FIG. 2, the remaining pressure elements having parallel end faces. FIG. 16 shows the wedge piece 61 (identical in shape with piece 61') as longitudinally slitted at 61a, thereby giving clearance to the cable 8 and the surrounding coil spring 65 when the piece 61 is clipped onto or pulled off the armature core in the slackened state thereof. Accidental detachment of the wedge pieces 61, 61' is prevented by a pair of clamps 62, 62' which, together with a common transverse strap 62 riveted thereto at 60 and 60', embrace the two wedge pieces and are held in firm contact therewith by the radially outward pressure of springs 65. This clamping pressure prevents any rotation of wedge pieces 61 and 61' about their axes, relative to the remainder of the respective column and the associated supporting body, thereby insuring that the two armatures 10, 10' remain curved in parallel planes perpendicular to the plane defined by bars 53-55. The bending of the armature 10 upon a maximum tensioning of its cable 8 has been illustrated in phantom lines in FIG. 2.

One or more additional straps 62a, embracing some of the ordinary pressure elements 7 and 7', can be used to impart additional stability to the structure.

Some of elements 7 and 7' may also be longitudinally slitted, as shown at 7a and 7a', to facilitate their removal from the column for replacement by wedge pieces 61, 61'. Special clamps such as those associated with strap 60a may help prevent untimely detachment of these slitted pressure elements.

In FIG. 3 there is shown an armature imbedded in a body 70, e.g., a cushion of foam plastic or the like, which includes a tension cable 64 surrounded by a coil spring 65 and threaded through a series of regular cylindrical pressure elements 66 with parallel end faces interspersed with wedge pieces 67, 68, 69 of trapezoidal axial cross-section. These wedge pieces may have longitudinal throughgoing slots 68a, as illustrated for the piece 68 in FIG. 17, and are shown surrounded by respective clamping rings 71, 72, 73 having external ribs 71a, 72a, 73a which bite into the surrounding foam material to prevent appreciable rotation of the rings and therefore of the wedge pieces about their axes. The clamping rings 71-73 may be slid onto an adjoining pressure element 66 when it is desired to remove the corresponding wedge piece from the column, with or without replacement of that wedge piece by another slitted element of different profile.

FIGS. 9 and 10 show a column of cylindrical and straight-faced pressure elements 74 on a cable 64, some of these pressure elements being embraced by slightly larger longitudinally slitted sleeves 77 with segmental end flanges 75, 76 of wedge-shaped, substantially triangular cross-section projecting unilaterally between adjoining elements 74 to hold them at an angle to one another, thereby again imparting a certain curvature (here an upward camber) to the column. A reduced tongue 78 defines with the flanged part of the sleeve an axially extending slot 77a by which it may be clipped onto any pressure element 74 in the slackened state of the armature. When the cable 64 is stretched taut, the clamping pressure exerted upon flanges 75 and 76 by the adjoining elements 74 prevents any relative rotation of wedge piece 77. If desired, several such wedge pieces may again be interconnected by transverse straps, similar to the one shown at 63 in FIGS. 1 and 2, for simultaneous attachment to and removal from adjoining armatures.

FIG. 6 schematically illustrates a complete reinforcing structure according to the invention, including a series of parallel armatures 84 terminating in cross-bars 85, 86 against which their tension members may be stressed by any suitable means such as the various tensioning devices described in my above-identified prior patent. Depending upon the number and shape of the inserted wedge pieces, the structure can be given a more or less pronounced curvature as illustrated at (a), (b) and (c) in FIG. 6.

FIGS. 7 and 8 show a wedge piece 89 of sickle-shaped cross-section fitting onto a tension cable 88 without interposition of any coil spring or the like. FIGS. 11-13 show a similar wedge piece 89 in the form of a somewhat wider sleeve 90 of the same generally sickle-shaped profile and trapezoidal axial section defined by two beveled end faces 91, 92 which carry elastically compressible layers 93 and 94 of complementarily tapering profile. In their uncompressed state (FIG. 11), the outline of unit 89 is substantially rectangular so that, as long as the compression resistance of layers 93 and 94 exceeds the stress of the associated tension cable, the part of the column containing this unit together with similar or ordinary (straight-faced) compression elements remain substantially straight. When the cable tension is increased, the column flexes progressively in the direction of divergence of end faces 93, 94.

In FIGS. 14 and 15 I have illustrated a unit 89' of this general construction provided with extensions 95, 96 on its sleeve 90' for precompressing the resilient layers 93', 94' on its end faces 91', 92' independently of the cable-stressing mechanism. These extensions, articulated to the sleeve by hinges 97, 98, form a pair of tongs whose clamping pressure may be adjusted by a holding screw 99 with the aid of a nut 99a. With the hinged ends of these tongs bifurcate, as shown, their presence does not prevent an expansion of the slotted sleeve to slip it onto or remove it from an associated tension cable. If such removal is not required, the sleeve could of course be completely tubular, with the bifurcate tong extremity replaced by a ring.

The armature embodying the present improvement need not be constituted by a single column but may be subdivided into several columns with independently tensionable cables or the like.

The stressing of the tension member or members may be carried out by hand, as illustrated in FIG. 4, or by automatic means including conventional sensors responsive to ambient conditions such as temperature, electric or magnetic fields, gravity, centrifugal forces and the like. For hospital use, the stress of the tension members and therefore the curvature of the patient's mattress or other body support may be controlled by instruments measuring such medical data as respiration, pulse rate or heartbeat. It is also possible to vary this tension in a diurnal rhythm under the control of an automatic timer.

Finally, it should be noted that the invention in at least some of its aspects is not limited to wedge pieces threaded onto a central core. Elements such as those shown at 89 in FIGS. 11-13, for example, could be inserted end-to-end (or with interposition of straight-faced cylindrical blocks) in an elastic hose acting as the tension member, e.g., as shown in FIGS. 13-15 of my prior U.S. Pat. No.3,492,768; in this case, of course, the beveled compression elements need not be tubular but may be completely solid.

Claims

I claim:

1. A reinforcing structure for a load-supporting body, comprising:

at least one elongate tension member anchored to said body;

a column of mutually abutting pressure elements of generally tubular shape traversed by said member, at least one of said elements being wedge-shaped for imparting curvature to said column, the adjoining elements having parallel end faces;

stressing means engaging said member and said column for selectively slackening and rigidifying the latter; and

retaining means individually engaging said wedge-shaped element for holding same against rotation relative to said body in both the slackened and the rigidified state of said column.

2. A reinforcing structure as defined in claim 1 wherein said wedge-shaped element is a resilient sleeve with a longitudinal throughgoing slot for clearing at least said tension member.

3. A reinforcing structure as defined in claim 2 wherein said sleeve has beveled end faces and elastically compressible layers on said end faces.

4. A reinforcing structure as defined in claim 3 wherein said sleeve is provided with a pair of tongs hingedly connected therewith at said end faces and bearing upon said layers with adjustable pressure.

5. A reinforcing structure as defined in claim 2 wherein said sleeve has a generally sickle-shaped cross-section.

6. A reinforcing structure as defined in claim 1 wherein said tension member is received with annular clearance in said pressure elements, further comprising a coil spring in said clearance tending to spread said wedge-shaped element outwardly against said retaining means.

7. A reinforcing structure as defined in claim 1 wherein at least some of said pressure elements are longitudinally slitted for lateral removal from said tension member in the slackened state of said column.

8. A reinforcing structure for a load-supporting body, comprising:

at least one elongate tension member anchored to said body;

a column of mutually abutting pressure elements of generally tubular shape closely juxtaposed with said member, at least one of said elements being a sleeve of generally trapezoidal axial cross-section with two nonparallel end faces imparting curvature to said column, said sleeve being provided with an extension hingedly connected therewith at said one of said end faces for bearing upon said layer with adjustable pressure;

An elastically compressible layer of tapering thickness on at least one of said end faces;

stressing means engaging said member and said column for selectively slackening and rigidifying the latter; and

holding means independent of said stressing means engaging said extension for maintaining said pressure at a selected value corresponding to a desired curvature of said column.

9. A reinforcing structure for a load-supporting body, comprising:

a plurality of armatures each including an elongate tension member and a column of mutually abutting pressure elements of generally tubular shape traversed by said member;

stressing means engaging said member and said column for selectively slackening and rigidifying each armature;

at least one wedge piece of generally tubular shape detachably inserted between two of said elements and traversed by said member for imparting curvature to said armature in the rigidified state thereof;

and retaining means engaging said wedge piece for holding same against rotation relative to said body in both the slackened and the rigidified state of said column, said retaining means interconnecting corresponding wedge pieces of said plurality of armatures.

10. A reinforcing structure as defined in claim 9 wherein said retaining means includes a strap transverse to said armatures.

11. A reinforcing structure for a load-supporting body, comprising:

at least one armature including an elongate tension member and a column of mutually abutting pressure elements of generally tubular shape traversed by said member;

stressing means engaging said member and said column for selectively slackening and rigidifying said armature; and

a resilient sleeve with a longitudinal throughgoing slot clipped onto one of said elements and formed with at least one segmental end flange unilaterally projecting between said one of said elements and an adjoining pressure element for partly separating same from each other while being clamped in position therebetween.