US3606464A

US3606464A - Chair

Info

Publication number: US3606464A
Application number: US809562A
Authority: US
Inventors: Theodore K Arbuthnot
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-03-24
Filing date: 1969-03-24
Publication date: 1971-09-20
Anticipated expiration: 1988-09-20

Abstract

A CHAIR HAVING THE LENGTH OF THE SEAT APPROXIMATELY EQUAL TO THE DISTANCE FROM THE FRONT OF THE SEAT TO THE CHAIR TO THE FLOOR, WITH THE SACRAL BRACE TILTING BACKWARD AT AN ANGLE OF 95* FROM THE FLOOR TO THE SACRAL BRACE TO SUPPORT THE SACRUM, THE SEAT TILTING DOWNWARDLY FROM THE FRONT OF THE SEAT TO THE BACK OF THE SEAT BETWEEN FIVE AND EIGHT DEGREES OF DECLINATION, ARM RESTS PARALLEL TO THE SEAT WITH THE RELATIONSHIP OF THE DISTANCE FROM THE BACK OF THE ARM REST TO THE BACK OF THE SEAT AND THE BACK OF THE SEAT TO THE FLOOR AT A RATIO OF THREE TO FIVE, AND THE BACK OF THE CHAIR TILTING BACKWARD AT AN ANGLE OF ONE HUNDRED DEGREES FROM THE FLOOR TO THE BACK OF THE CHAIR.

Description

Sept. 20,- 1971 ;T. K, ARBUTHNOT CHAIR Filed March 24, 1969 I N VEN'IOR.

1 Z I THEODORE mARau-rmm' BY 7 f ATTURNEY United States Pat fi 3,606,464 CHAIR Theodore K. Arbuthnot, 3233 NE. 34th St., Apt. 1210, Fort Lauderdale, Fla. 33308 Filed Mar. 24, 1969, Ser. No. 809,562 Int. Cl. A47c 7/00, 7/20 US. Cl. 297-460 6 Claims ABSTRACT OF THE DISCLOSURE A chair having the length of the seat approximately equal to the distance from the front of the seat to the chair to the floor, with the sacral brace tilting backward at an angle of 95 from the floor to the sacral brace to support the sacrum, the seat tilting downwardly from the front of the seat to the back of the seat between five and eight'degrees of declination, arm rests parallel to the seat with the relationship of the distance from the back of the arm rest to the back of the seat and the back of the seat to the floor at a ratio of three to five, and the back of the chair tilting backward at an angle of one hundred degrees from the floor to the back of the chair.

BACKGROUND OF THE INVENTION This invention relates to a new and improved chair, and, more particularly, to a chair supporting ones spine in a position when seated that is similar to the position of the persons spine in a standing position.

As is perhaps well-known, when a human is in a standing position, from a physiological anatomical standpoint, he provides a freedom of function for all organs Within the thorax and abdomen. The same freedom of function has not been made available to humans sitting in chairs designed in the past. Such chairs have been designed in an attempt to provide only structural support of a human. The

previously designed chairs have not incorporated all the essential elements that are necessary to provide the freedom of function of a human in a seated position.

SUMMARY OF THE INVENTION The present invention relates to a new and improved chair having five essential design features to provide a human with the same freedom of function in a seated position as he has in a standing position. The chair has a ratio of approximately one to one (1:1) between the distance from the front of the seat of the chair to the floor and the distance of the front of the seat to the back of the seat, a sacral brace tilting backward at an angle of ninetyfive degrees from the floor to the sacral brace to support the sacrum and in turn support the spine, the seat tilting downwardly from the front of the seat to the back of the seat between five and eight degrees of declination, arm rests parallel to the seat with a ratio of three to five between the height of the arm rest above the back of the seat and the height of the back of the seat above the floor support, and the back of the chair tilting backward at an angle of one hundred degrees from the floor to the back of the chair. The back of the chair may provide a neck rest or head rest which would extend anteriorly from three to four inches to correspond with the anterior curve at the occupants neck.

It is an object of this invention to provide a chair for a human providing the same freedom of function in the sitting position, as he would obtain in a standing position.

It is another object of this invention to provide a chair with a ratio of approximately one to one between the distance from the front of the seat of the chair to the floor and the distance of the front of the seat to the back of the seat.

Another object of this invention is to provide a chair with a sacral brace tilting backward at an angle of ninetyfive degrees from the floor to the sacral brace.

Another object of this invention is to provide a chair with a seat tilting downwardly from the front of the seat to the back of the seat between five and eight degrees of declination.

A further object of this invention is to provide a chair with arm rests parallel to the seat with a ratio of three to five between the height of the arm rests above the back of the seat and the height of the back of the seat above the floor.

Another object of this invention is to provide a chair with the back of the chair tilting backward at an angle of one hundred degrees from the floor to the back of the chair.

An additional object of this invention is to provide a chair with all of the features set forth in the objects hereinabove.

In accordance with these and other objects which will be apparent hereinafter, the instant invention will now be described with particular reference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING In the drawing:

FIG. 1 is a side view of the chair partially cut away illustrating a human therein;

FIG. 2 is a partial side view of the chair showing various design angles; and

FIG. 3 is a perspective View of the sacral brace.

DESCRIPTION OF THE PREFERRED EMBODIMENT 'Referring now in detail to the drawing, wherein an embodiment of the invention is shown, and, referring, particularly, to FIG. 1, the chair, generally designated at numeral 2, is placed on floor 4. The floor also supports the feet of the occupant of the chair 2. The chair includes legs, 6 and 8 are shown, a seat base member 10, a seat 12, a back or back brace 14, a sacral brace 16, and arm supports, arm support 1 8 is shown. The back brace 14 may include a neck support or neck and head support extension 20.

The chair shown in FIG. 1 includes five basic design features that take into account some very pertinent anatomical facts, as well as the great flexibility of body tissues. The human is not locked in the chair illustrated in the drawing, in any one position and he may change position without discomfort. It should be noted that in the standing position the normal spine has three curves, two anterior and one posterior. The first anterior curve begins at the base of the skull and extends to the fifth cervical vertebra. The second anterior curve begins at the junction of the third and fourth lumbar vertebrae and extends to the coccyx. The posterior curve begins at the first dorsal and extends to the third lumbar vertebra. In the standing position the contents of the thorax and abdomen are hanging normally from. their spinal or other attachments and are free to perform their physiological functions without hindrance from compression or circulatory obstructions. The chair 2 provides support for the person in the sitting position. that closely approximates the humans standing position. The average living room or den chair does not provide such support because it is so constructed as to force the spine into one big posterior curve. In the average chair the contents of the thorax and abdomen are subject to a compression which is not desirable, particularly to those humans who have disabilities of the heart, lungs and other physiological conditions which require the best of circulation. To negate this undesirable feature, chair 2 permits the spine to assume a position more nearly approximating the standing position. The occupant is completely at rest without muscle tension supporting various parts of his body.

Proper support for an occupant of a chair is provided in the disclosed chair design. In the past, a number of chairs have been built with cross bars at the level of the anterior lumbar curve, that is, the hollow of ones back. Some chairs have been built with a cross bar at a higher position in the dorsal area of ones back. Such cross bars, positioned at the anterior lumbar curve or in the dorsal area, may force an occupant of the chair into an erect posture but that type of bracing action will also lock the muscles of the occupants back into steady tension. If ones muscles are held in steady tension over a long period fatigue will set in. The proper basis of spinal support is at the sacrum. If a person sits on a bench, completely relaxed, he will have a very slumped position and his spine will show one big posterior curve from the neck to the coccyx. When the surface of the sacrum is firmly supported the person may relax but he will be unable to slump. His back muscles will not be in tension and no fatique will set after sitting for a relatively long period of time. To design the type of back support disclosed herein, a sacral brace 16 is incorporated in the chair as shown in the drawing. The sacral brace 16 slopes backward at a ninety-five degree angle to the floor 4 as shown in FIG. 2. The anterior face of the sacral brace may be bonded with a polyurethane foam from /8" to A" thick.

It should be noted that the distance from the hollow of the bended knee, shown at point 22, to the floor 4 Will be the same as the distance from the hollow of the knee, shown at point 22, to a line at the base of the sacrum 24. Most of todays living room or den chairs average between 19 and 21 inches in seat depth. Divan seats will usually be about 23 inches. A person whose knee to floor measure is only 15 to 18 inches cannot sit with his sacrum against the back of the chair. The spine will assume the one big posterior curve. Since people come in many different sizes, in order to design a chair that will place the sacrum of a person against a sacral brace, different size chairs must be constructed. In the design of the disclosed chair 2, the measurement of the seat from the front of the seat to the back of the seat in relation to the measurement from front of the seat to floor will be approximately a one to one ratio. This ratio will remain constant for all size chairs. The height of the front of the seat 12 from the floor is approximately equal to the distance from the front of the seat 12 to the back of said seat. An allowance of up to one inch may be used in designing the seat length to accommodate the extra flesh lateral to the sacrum.

Seat 12 slopes downwardly from the front edge in order to prevent the necessity of the occupant to tense his muscles to maintain this position. When the seat is horizontal the occupant would have a tendency to lean forward. Therefore, to make the occupants position one of a relaxed person, that is, relatively free of muscle tension, especially in his back muscles, the seat 12 of the chair 2 slopes downwardly from the front of the chair. The proper angle of declination from front of the chair to the back of the chair is between five to eight degrees. The particular angle used may be left to the art of the designer. The preferred angle is between six and seven degrees. For example, the angle of declination may be 6.4 degrees which holds the occupant in the seat in a relaxed erect position.

The chair has arms 18 to support the occupant. If arms are not provided at a sufiicient height, the muscles of the shoulder girdle will impel a general slump. The arms 18 of the chair 2 should be high enough for the elbow to rest on the arms to support the shoulder girdle without tension on the shoulder muscles. The arms 18 of the chair 2 should parallel the upper surface of the seat 12 and should extend for at least 16 inches from the back rest 14. Longer arms may be desirable but can be left to the art of design. The height of the arm from the back of the seat in relation to the height of the back of the seat from the floor is a constant ratio of 3 to 5. This ratio is held for all size chairs.

An important consideration is constructing the shape of the back 14 of the chair 2 is that the posterior curve of the back of an occupant should rest comfortably in the chair 2 Without undue pressure in any one spot. This may be achieved by designing a curve running from the top of the sacral brace 16 to near the top of the occupants back at point 26, using relatively firm upholstering or having a straight back thickly padded with a soft upholstering which Would permit the back to settle into its proper curve. Also it may be desirable to have the upper four inches of the back, shown at 20, with a pad extending three to four inches forwardly to accommodate the anterior curve in the neck region or to serve as a head rest.

The back of the chair is sloped backwardly at an angle. A tangent drawn through the curve-d front side of the back of the chair as shown in FIG. 2 intersects the floor 4 at an angle of one hundred degrees as shown in FIG. 2. The line drawn through the sacral brace intersects the floor at an angle of ninety-five degrees. Therefore, the five degree difference between the angle of the sacral brace and the back of the chair provides the bracing effect to support the occupant.

The details of the sacral brace 16 are shown in FIG. 3. With the chairs occupant seated in seat 12 and with the sacrum and buttocks of the occupant placed against the sacral brace 16, the occupant is in a completely relaxed position. The sitting posture is near the occupants standing posture. The chair allows the body to be adjusted in the chair, the chair 2 does not lock the occupant in one position.

The instant invention has been shown and described herein in what is considered to be the most practical and preferred embodiment. It is recognized, however, that departures may be made therefrom Within the scope of the invention. Therefore, the instant invention is not to be limited to the details discussed herein, but to be accorded the full scope of the claims so as to embrace any and all equivalent apparatus and articles.

What is claimed is:

1. A chair comprising:

supporting members,

a seat member connected to said supporting members,

a back member connected to said seat member, said back member including a concave front supporting surface adapted to support the back of a person occupying the chair, the greater portion of said supporting surface generally slopes upwardly and rear- Evardly when viewed from a point on said seat mema sacral brace connected to said back member adapted to make contact with the sacrum of the person occupying the chair to support the sacrum of the person, said sacral brace slopes upwardly and rearwardly when viewed from a point on said seat member.

2. A chair as set forth in claim 1 wherein,

said seat slopes downwardly from the front of said seat to the back of said seat at an angle between five and eight degrees.

3. A chair as set forth in claim 2 wherein,

the relationship of the length of said seat to the height of the front of the seat from a floor is approximately a one to one ratio.

4. A chair comprising:

supporting members,

a seat member connected to said supporting members,

a back member connected to said seat member,

a sacral brace connection to said back member for contact with the sacrum of an occupant of the chair to support the sacrum of the occupant,

the front supporting surface of said back member is concave when the back of the occupant is supported by said back member,

a line drawn tangentially to the most rearward portion of said concave surface intersects a horizontal line at an angle sloping rearward from a point below an upper point on said tangential line,

a line drawn parallel to the front surface of said sacral brace intersects a horizontal line at an angle sloping rearward from a point below an upper point on said parallel line,

said seat slopes downwardly from the front of said seat to the back of said seat at an angle between five and eight degrees,

the relationship of the length of said seat to the height of the front of the seat from a floor is approximately a one to one ratio, and

arm rests connected to said chair, the relationship of the height of the arm rest from the back of the seat to the height of the back of the seat from the floor is approximately a three to five ratio.

5. A chair as set forth in claim 4 wherein,

said angle sloping rearward from a point below an upper point on said tangential line is approximately one hundred degrees.

6. A chair as set forth in claim 5 wherein,

said angle sloping from a point below an upper point on said parallel line is approximately ninety-five degrees.

References Cited UNITED STATES PATENTS 458,140 8/1891 Bangs 297460 856,058 4/1907 Hanger 297-460 1,210,223 12/1916 Silbert 297460 1,917,264 7/1933 Kellogg 297459 CASMIR A. NUNBERG, Primary Examiner US. Cl. XR,