US2756809A - Back support for chairs, car seats, and the like - Google Patents

Description

July 31, 1956 ENDRESEN 2,756,809

BACK SUPPORT FOR CHAIRS, CAR SEATS, AND THE LIKE Filed June 50, 1954 United States Patent BACK SUPPORT FoReirAiR's, SEATS, AND THE LIKE Ernst Endresen, St'a'vaiiger, Norway Application June 30, 1954, Serial No. 440,517

3 Claims. (Cl. 155-182) The invention relates to an improved back support for chairs, car seats and the like such as back rests for hospitals, specially designed to counteract and prevent pains in the back, such as sciatica, lumbago and the like, and is concerned primarily with a back rest of the kind consisting of a relatively stiff plate adapted to follow the lines of the human back and having a lower convex part and an upper concave or straight part, the curves of the plate being adjustable by means such as screws which can be manipulated to increase or decrease the convexity and concavity of the plate to suit the seated person.

The arrangement according to the present invention is characterized in that means are provided for moving the ridges of the curvatures in the longitudinal direction of the plate and for adjustment of the transition curve between the shaped parts thereof. Efficient means are thereby obtained whereby the form of the plate can be adjusted in accordance with the particular contour of the back of the seated person, such backline differing from person to person. The back support is specially designed to be placed in the drivers seat of buses and motorcars, but can also be used in hospitals by being placed in bed for a pa tient to lie on or as a back rest.

One example of the device is shown on the accompanying drawing wherein:

Figure 1 shows a longitudinal section taken on the line 1-1 of Figure 2;

Figure 2 is a front view of Figure l and Figure 3 is a horizontal cross section taken on the line 3-3 of Figure 2.

The back support consists of a flexible steel plate 1, mounted for example in a chair frame 2, the back of which is closed by a back plate 6. The lower edge of the steel plate 1 is fastened around a bolt 3 and at the top the upper end is fastened around a bolt 4 slidable in a vertical groove 5, so that the plate has a certain latitude of up and down sliding movement when the curves thereof are regulated.

When the back is adjusted in accordance with a persons back lines, the lower part of the plate 1 must be more or less convex and its upper part more or less concave (or if necessary straight). Convexity and concavity is regulated by means of two screws 7 and 8 which are moved in and out by means of nuts 11 and 12 respectively. The screws '7, 3 have secured at their outer ends crossbars 9 and it), which support the plate 1 transversely, the crossbars 9, being provided with hooked ends 9a and ltla respectively which grip around the side edges of the plate 1. The screws 7, 8 also extend through holes in transverse plates 15 and 16 respectively which are of channel-form in cross section and rest against the side rails 2 and the back plate 6 of the chair frame. The plates 15 and 16 are adjustable vertically so that the ridges or 2 tops of the convex and concave plate parts may be moved in the vertical direction of the plate so that the curves of the plate and the transition curvebetween the convex and concave parts can be altered in-the required manner.

The cross-bars 9, '10'are guided in slots 9b, 101) in the sideflanges of theplate's 1'5, 1'6, aiidin'o'r'der'tb enable vertical iribvemeiits'ofthe nuts11,'1 2, slots 19, 20 are provided in the back plate 6.

To each plate 15 and 16 is fastened a threaded chock which engages screws 13 and 14 operable by means of nuts 17 and E8. Rotation of the nuts 17, 1-8 will cause the plates 15, 16 to be raised or lowered and thereby also the screws 7 and 8 and the cross-bars 9 and 10. In this manner the top points or ridges of the convex and concave parts of the plate 1 are raised or lowered to fit the lines of the back of a seated person, and the transition curve between the two curved parts may also be adjusted, by moving the supporting bars 9 and lit closer together or further apart from each other. Full control of the curves of the back plate 1 is thereby gained and they may be closely adjusted to fit any personal back line.

The whole adjustment may be effected quickly by means of the four nuts 11 and 12 and 17 and 18. The back support may be mounted to swing within a limited angle, in the vertical plane, in a chair frame, so that the cant of the back support may be adjusted while a person is sitting in the chair or seat. The steel plate 1 may be provided with padding and in this case a vertical depression or thinning out in the padding may be arranged vertically in the middle of the back so that the vertebrae are not exposed to pressure. The back support may be mounted so that it can be raised or lowered in the chair frame.

It will be appreciated that constructional detail concerning the chair or seat frame in which the back is fitted may be altered in many ways, the regulation of the ridges of the convex and concave plate parts thereof and the regulation of the transition curve between these two curved parts being the essential features of the invention.

What I claim and desire tosecure by Letters Patent is:

1. A back support for chairs and the like, consisting of a relatively stiff back plate mounted in a chair frame, said back plate being capable of adjustment to the back line of a user, said plate having a lower convex part and an upper concave part, screw means for adjusting the convexity and concavity of said parts and means for adjusting the position of the ridges of the convex and concave parts, said screw means being adjustable in the same direction to control the transition curve between said parts of the plate, vertically slidable plates of channel cross section mounted in the chair frame and carrying said screw means for adjusting the convexity and concavity of the back plate, cross-bars forming part of said screw means, hooked ends to said cross-bars adapted to grip the side edges of the back plate and form a support therefor, said slidable plate being provided with side flanges and said flanges having slots therein to serve as a guide for the said crossbars.

2. A back support for chairs and the like comprising a relatively stitf back plate mounted in a chair frame, said back plate being capable of adjustment to the back line or" a user and having a lower convex part and an upper concave part with ridges defining the same, screw means for adjusting the convexity and concavity of the said convex and concave parts and means for adjusting the position of the ridges of the said convex and concave parts in a vertical direction, said screw means being adjustable in the same direction to control the transition between the convex and concave parts of the plate and including supporting cross bars at their outer ends adapted to support the back plate transversely, the said supporting cross bars having hooked ends adapted to grip the side edges of the back plate.

3. A back support for chairs and the like comprising a relatively still back plate mounted in a chair frame, said back plate being capable of adjustment to the back line of a user and having a lower convex part and an upper concave part with ridges defining the same, screw means for adjusting the convexity and concavity of the said convex and concave parts and means for adjusting the position of the ridges of the said convex and concave parts in a vertical direction, said screw means being adjustable in the same direction to control the transition between the convex and concave parts of the plate, said plate being provided with padding which is vertically thinned out centrally thereof.

References Cited in the file of this patent UNITED STATES PATENTS 958,356 Bode May 17, 1910 1,264,265 Brusius Apr. 30, 1918 1,677,584 Cronwell July 17, 1928 1,937,920 Smith Dec. 5, 1933 2,359,318 Lay et a1 Oct. 3, 1944 2,549,902 Hibbard et al. Apr. 24, 1951 2,550,831 Lingenfelter May 1, 1951 FOREIGN PATENTS 2,598 Great Britain 1899

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