US 1961641 A
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H. F. OLLIS CHAIR SEAT June 5, 1934;
Filed Sept. 7, 1935 clean.
Patented June 5, 1934 UNITED STATES CHAIR SEAT Harry F. Ollis, Ashland, Mass., assignor of onehalf to Daniel F. Shaughncssy, Ashland,
Application September 7, 1933, Serial No. 688,487
The principal object of this invention is to provide a construction of chair seat preferably accompanied by a cushion of such a nature that the bones of the occupant, that is the pelvis and 5 thighs, or either, can be supported on a rigid seat with a cushion over it in such a manner that there will be no direct support for the said bones from the rigid chair seat itself but this cushion will be concaved out of 1 its normal shape by the weight of the occupant and the support for that part of the buttocks and legs in which the bones are situated will come from a space or spaces bridged by the suspended cushion and not backed up directly by the hard seat. Other objects of the invention are to provide a construction of seat which will be strong and durable and will not involve any material expense greater than that ordinarily employed for a seat of a similar character not having the characteristics of this in- 2 vention; and to provide a construction for preventing the reacting pressure throughout the area of primary contact between the normal or natural human seat and the usual hard chair seat, thereby destroying the cause of most of the 5 discomfort arising from the use of ordinary chairs an chair seats. This is accomplished according to this invention by providing a space in the chair seat which may be in the form of deep channels, or perforations all the way through the seat, and which are located directly under the pelvic and thigh bones of the occupant so that when sitting on the, chair, a soft cushion/provided on the top of the seat will be 99 aved and flexibly suspended in those po rtions under which the said bones are located/Said spaces are wide enough to permit this and narrow enough to prevent the cushion descending too far into the space or contacting with the bottom of such a channel, whereby a flexible suspended support is provided 40 in parts of the whole seat with'its cushion over' which these bones are located and they are entirely relieved from any reactive pressure from the hard surface of the seat itself and yet they are supported adequately.
Other objects and advantages of the invention will appear hereinafter.
Reference is to be had to the accompanying drawing, in which Fig. 1 is a perspective view of the rigid part of a chair seat constructed in accordance with'this invention;
' Fig.2 is a side view of the same as indicated by the arrow 2 in Fig. 1 with the cushion in position; and
Fig. 3 is a sectional view on the line 3-3 of Fig.1 on enlarged scale showing the position of the legs and thighs of the occupant of the seat, and showing the flexing of the cushion.
I have found, after extensive experience in this industry, that no provision has yet been made to provide" proper and adequate escapement for; the pressures that are impressed upon certain definitely located areas of the human seat in sitting in a chair. Cushions are employed but they are always backed up by hard unyielding surfaces and they cannot provide for the escapement'of this pressure as the cushion is quickly forced to its compression limit. At the areas of greatest protrusion of the human seat at which most of the weight of the occupant is necessarily localized, there shouldbe a truly yielding surface which is not subject to the above difficulty. I provide a cushion which is not only soft and resilient, but also elastic and under such mechanical conditions that the greatest possible amount of its elasticity may be utilized to relieve the body of the reaction that comes from the seat of the chair. My chair seat is intended to be used with a cushion in such a way that this elasticity can be utilized for the purpose of providing a yielding suspended foundation on which the parts of the human seat in which the bones are located can pressure heretofore thought necessary.
Referring to the drawing, the seat may be wood 8 and can be made perfectly fiat if desired without the necessity and the expense of providing shallow. depressions in. it for fitting the human seat. It is provided with a space or spaces 2 for the relief of the bones mentioned. In the form shown, these spaces are illustrated as extending clear through the seat and of a general U shape opening at the front, thus dividing the seat into two parts,- the outside portion 1 and an inside portion 1. as shown or in the form of deep channels so deep that the rubber cushion 4 will never touch the bottom of them.
While in the form shown these two parts are not integrally connected together, they are shown as being rigidly connected together by cross bars 3 and the tops of both sections of the seat are located preferably in the same plane. This seat is used in connection with a' soft flexible resilient cushion 4 which can be made of any material having those qualities but I prefer sponge rubber. Preferably it extends throughout the area of the rigid seat and at least extends over the spaces 2. It can be secured to the seat 1 by any desired means. 1
The spaces 2 can be made 9 x This U shaped space is shown with the two sides slightly diverging toward the front so as to provide a space for the pelvic bone and two forwardly extending spaces, preferably connected therewith, for the thigh bones. The cushion is made of suitable thickness, preferably lying flat on the seat as shown in Fig. 2. When an occupant seats himself on this chair seat, his pelvis will normally rest on the cushion above the rear or transverse part of the space 2 while the thighs will extend forward directly over the side spaces constituting a part of this space 2.
In Fig. 3 the result is indicated. It will be obvious that the weight of theoccupant will depressthe cushion or concave it'and that part of it will project down into the spaces both at the rear and along the sides. This space is sufficiently wide to allow the cushion to flex down into it but not wide enough to permit it to touch the bottom of the channel or' to extend down to the bottom of the chair seat. On account of the generally convex contour of the human seat, a moderately narrow line drawn along the center of this U-shaped space throughout the entire length thereof will represent the line of primary contact where actual contact first occurs. In ordinary chair seats, this is also the area of major support and consequently of maximum pressure. The remainder of the actual contact area with the seat will thereby constitute an area of secondary contact. Pressures which develop within this latter area of an ordinary chair seat obviously will be considerably less severe than those that develop in the area .of primary contact, which lies directly below in vertical alignment with the large structural bones. Since the nor- -mal pressures which accompany the occupation of a chair seat are the result of the action of gravity upon the weight of the occupant, they cannot be entirely avoided. The discomfort,
however, which they cause is not entirely de-- pendent on the intensity of the pressure but is influenced largely by the relative sensitivity to pressure of the individual area at which they.
occur and the physical and anatomical conditions existing within such area.
It is evident that when the line of major support is located directly below a large bone, an intense pressure will quickly develop at that point even when a cushion is used, thereby producing a painful squeezing compressive action. This affects the muscles, nerves, veins and arteries which lie directly below the said bone and directly above the said line of major support. It is this specific and entirely objectionable condition which at present generally prevails in chair seats that is aVOided b y this invention. By my invention this area of primary contact, as herein defined, is definitely excluded from the area of major support.
Referring to Fig. 3, the areas enclosed by the dotted circles 5 indicate the approximate positions of the right and left legs of the occupant. The parts 6 indicate the position of the corresponding respective thigh bones. The line of primary contact is at '7 but it is to be noted here that, although in an ordinary chair seat this is the line of major support, in the present case that is avoided. This area is supported by the flexible suspended cushion with no solid backing behind it. Areas 8 which constitute points of secondary contact and would constitute areas of minor support in an ordinary chair seat in this case constitute the areas of major support and function as such.
It will be seen therefore that the areas of major support of an ordinary chair seat are removed and in place of it a flexible resilient body is placed under the. leg at this point and the areas of major support are spaced apart at the sides where both the areas are larger and .the pressure is distributed. Therefore there is no serious reactive pressure against the legs of the occupant and a really comfortable chair seat is provided. In this way the pressures incident to the support of the weight of an occupant of my chair seat are transferred to and impressed upon areas of the human seat which'foranatomical reasons are much less sensitive to pressure and therefore better adapted to sustain them without discomfort or injury.
This application is in part a continuation of my copending application Serial No. 454,042, filed May 23, 1930:
Although I have illustrated and described only one form of the invention, I am aware of the fact that modifications can be made therein by any person skilled in the art without departing from claims. Therefore, I' do not wish to be limited to all the details of construction herein shown and described, but what I do claim is:-
1. As an article of manufacture, a rigid chair seat having a flexible cushion over the part thereof that directly supports the pelvis and thighs of the occupant, said cushion being co-extensive with the seat, said se'at having a narrow deep space therein of such shape as to receive thereabove the pelvis and thighs of the occupant to permit the cushion to be flexed thereby into said space a short distance to directly support the pelvis and thighs from a freely suspended portion of the cushion. 2. As an article of manufacture, a rigid chair seat having a thick soft flat flexible cushion over the part thereof that directly supports the pelvis and thighs of the occupant, said cushion being coextensive with the seat, said seat having a narrow deep space therein of such shape as to receive thereabove the pelvis and thighs of the occupant to permit the cushion to be flexed thereby into said space a short distance, to prevent the pelvis and thighs being supported directly by a part of the seat directly below the part of the cushion on which-the pelvis and thighs rest.
3. As an article of manufacture, a substantially rigid flat chair seat having a substantially U- .shaped space entirely through the seat over which