Comfort support seat cushion assembly

A comfort support seat cushion assembly to alleviate discomfort of people that are required to sit for long terms. This comfort support seat cushion provides even pressure distribution on the gluteal region with pressure relief for the ischial tuberosities, coccyx, and perineum. A pulsating means can also be provided to administer therapeutic relief to assist in alleviating discomfort for long term sedentary positions. SU PAC BACKGROUND OF THE INVENTION This invention relates in general to a seat cushion assembly for supporting a human body. More particularly, this invention is directed to a comfort support seat cushion assembly that is specifically designed to alleviate discomfort, fatigue, pain, and decreased performance that accompanies long term sedentary positions. In addition, improved blood flow will result from the dynamic action that is part of this invention. It has long been recognized that there have been a multiplicity of contoured chairs, cushions, and seats that have been designed to improve the comfort of those human beings required to sit for long terms. Doctors have always been troubled with the problems of patients that spend long times in wheel chairs. These troubles stem from phlebitis to pressure necrosis, which occurs at points on the body where the bone structure of the patient is close to the supporting surface, such as is the case of the ischial tuberosities. In addition, more recently, biomedical specialists concerned with military aircraft cockpit design have not only noticed that the crew members suffer discomfort, fatigue and pain but also decreased performance efficiency. The lack of adequate support of the back and buttocks both hastens and intensifies the occurrence of these reactions. In the specific case of military aircraft that contains an escape mechanism in the form of an ejection seat, high dynamic forces are generated by the impact of the seat cushion on the buttocks region. Therefore, to alleviate potential spinal injuries, the amount and type of material which can be used between the ischial tuberosities and the seat pan is severely limited. Previous attempts to solve these problems have not recognized the importance of adequate weight distribution across the surfaces of the gluteal region. An inadequate weight distribution will result in excessive pressure on the ischial tuberosities. This is true for both a patient application, such as a wheel chair, and a military aircraft ejection seat application. It has been also recognized that massage in the gluteal region will give temporary therapeutic relief along the contact surfaces to persons who have been required to sit for long terms. A number of devices have been disclosed that produce an intermittent surface pressure variation or pulsating action on the gluteal region. Other devices have been disclosed that produce translational pressure wave movement for massaging effect. One such device is exemplified in the U.S. Pat. No. 3,613,671 to Poor, et al. This patent discloses an inflatable massaging pad which includes a plurality of spaced parallel inflatable cells. An inflation means is provided along with a distributor to produce a translational pressure wave through the cells and a massaging effect. A difficulty with this device is that the translational wave massage pumps the blood flow in both directions, away from the heart as well as toward the heart. The reverse direction, away from the heart, is potentially harmful due to the tendency to further reduce the natural blood flow and increase the potential for phlebitis. This device, therefore, would have little or no therapeutic effect but merely provide some temporary relief to the contact surface. PAC SUMMARY OF THE INVENTION It is, therefore, an object of the present invention to provide a comfort support seat cushion assembly that will alleviate discomfort and help eliminate fatigue, pain, and decreased performance efficiency that accompanies long term sitting. It is another object of the present invention to provide means of improving the blood flow in the gluteal region. It is still another object of the present invention to provide a fire resistant comfort support seat assembly tha can also be used in an ejection seat system where high dynamic forces generated by impact during escape limits the amount and type of material that can be used. Briefly, in accordance with the invention, there is provided a seat cushion assembly having a contoured support layer of a firm resilient foam material designed to provide an even pressure distribution over the gluteal region. Pressure relief for the ischial tuberosities is provided in the form of a hole cut in the support layer. Pressure relief for the coccyx is provided in the form of a foam material insert in the support layer. On top of the support layer, a comfort layer of medium resilient foam material is provided. Positioned on top of the comfort layer is a pressure distribution layer of soft foam material with an elongated hole in the central part to provide additional pressure relief for the perineum. A ventilation layer is also provided on top of the weight distribution layer to additionally alleviate discomfort due to increased moisture and body surface temperature. All of the layers are inserted into a porous cloth cover which has a manually operated closure. In another form of the invention, a plurality of inflatable tubes is inserted between the support layer and the comfort layer. The inflatable tubes have an inflating means and a sequencing means which provide transitional waves only from the legs toward the heart to improve the natural blood flow. Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings.

While the invention will be described in connection with the preferred 
embodiments, it will be understood that it is not intended to limit the 
invention to those embodiments. On the contrary, it is intended to cover 
all alternatives, modifications, and equivalents that may be included 
within the spirit and scope of the invention as described by the appended 
claims. 
DETAILED DESCRIPTION OF THE INVENTION 
Referring now to FIGS. 1-4, there is shown a support layer according to the 
present invention generally indicated at 10. This support layer 10 is 
comprised of a pad 12, preferably about 11/2 inches in thickness and about 
18 inches square although the corners may be shaped slightly to fit in a 
specific seat pan (not shown). The pad 12 is made of a resilient foam 
material, such as Ensolite.RTM. AF having a compression resistance range 
from 18 to 20 lbs/in.sup.2. A cutout 14, which is optimally elliptical, is 
provided in pad 12. The opening 14 is approximately 6 inches by 41/2 
inches and provides additional relief for the ischial tuberosites of the 
human body, in that the opening 14 accommodates the ischial tuberosities. 
An insert 16 is bonded in cavity 17 of the support cushion pad 12. This 
insert 16 is approximately 6 inches by 21/2 inches and is shown in 
elliptical shape although other shapes may be used. Insert 16, which is 
approximately 1 inch deep at the rear portion as best seen in FIG. 2, is 
beveled such that as it slopes forward it simultaneously becomes thinner. 
The insert 16 is comprised of a resilient foam material, such as neoprene, 
with a compression resistance range from 174 to 1 lb/in.sup.2 and 
provides additional relief for the coccyx of the human body by virtue of 
its soft characteristics. 
With reference to FIG. 2, the cutout 14 and the gouged out nature of area 
18 of the support layer 10 are clearly seen. Area 18 provides pressure 
relief for the perineum. FIG. 3 shows contouring 15 of the support layer 
10 and the cutout 14. FIG. 4 shows contouring 15 at a forward position of 
layer 10 and also shows the gouged out area 18. The contouring 15 of the 
support layer 10 provides an even pressure distribution in the gluteal 
region and will accommodate the majority of male gluteal regions, i.e. 
from the 5th to the 95th percentile. 
Referring to FIG. 5, there is seen the comfort layer generally indicated at 
20. This layer is the same shape generally as the support layer 10 and in 
the preferred embodiment fits directly and evenly on top of the support 
layer 10. The comfort layer 20 is composed of a resilient foam material, 
such as Ensolite .RTM.M, with a compression resistance range of 1 to 3 
lbs/in.sup.2 and is approximately 5/8" to 1" in thickness for a wheel 
chair type application and normally a maximum of 1/2 inch for military 
seat applications. As shown in FIG. 6, the thickness is optimally uniform. 
FIG. 7 is a plan view of the weight distribution layer generally indicated 
at 22. This layer which is about 1/2" in thickness is also preferably the 
same shape generally as support layer 10 and fits directly and evenly on 
top of comfort layer 20. An elliptical cutout 24 is made in the center 
portion of the weight distribution layer 22 and in the preferred 
embodiment is approximately 9 inches by 31/2 inches. This cutout 24 
prevents bunching of material in the center of the weight distribution 
layer 22 which would create pressure on the perineum. The weight 
distribution layer 22 is composed of a resilient foam material, such as 
neoprene, with a compression resistance range from 1/4 to 1 lb/in.sup.2. 
By virtue of this low compression resistance, layer 22 smooths out 
imperfections in contouring of the other layers. 
FIG. 8 which is a cross-section view of the weight distribution layer 22 
shown the uniform thickness of layer 22 and the chamfered edge of the 
ridge of the cutout 24. 
FIG. 9 illustrates the ventilation layer generally indicated at 24'. 
Preferably, this layer is approximately 1/4 inch in thickness and is made 
up of a porous, fibrous, woven material, such as space fabric, consisting 
of semi-rigid, porous tubes 26 (FIG. 10) sandwiched transversely between 
two layers of porous cloth 28 and 30. The cloth layers 28 and 30 are 
joined to the tubes 26 either by weaving or bonding. Ventilation layer 24' 
is optimally the same general shape as the support layer 10 and fits 
directly on top of the weight distribution layer 22. 
FIG. 11 illustrates the comfort support seat cushion assembly generally 
indicated at 32. A cutout 34 approximately 7 inches by 4 inches, can be 
made in the assembly 32, if desired, to accommodate a seat harness, such 
as would be the case if the assembly 32 were to be used as an aircraft 
crew seat. 
FIG. 12 is a cross section of the comfort support seat cushion assemby 32 
and illustrates the integration of the support layer 10, the comfort layer 
20, the weight distribution layer 22, and the ventilation layer 24'. In 
order to provide ease of handling and prevent dislocation of layers, the 
comfort layer 20, the weight distribution layer 22, and the ventilation 
layer 24' are preferably bonded together with a suitable bonding material. 
Also shown in FIG. 12 is the soft insert 16 that provides pressure relief 
of the coccyx. The entire assembly 32 is encased in a cover (not shown) 
composed of a porous, washable material with a fastening means, such as 
Velcro, preferably on the rear portion of the cover, that allows closing 
of the opening in the cover after the assembly is inserted. 
FIGS. 13 and 14 illustrate another embodiment of the comfort support seat 
cushion which is generally indicated at 36. Assembly 36 has a series of 
flexible air cells 38 spaced parallel and sandwiched between the support 
layer 10 and the comfort layer 20. Each of the flexible cells may be made 
of rubber, plastic, or an anagolous flexible material. It is found however 
that silicone rubber is an excellent material for those cells as it is 
both wear resistant (which produces a long life) and fireproof. FIG. 14 
shows the positioning of these cells 38 to the layers 10, 20, 22, and 24' 
of assembly 36. Layers 10, 20, 22, and 24' are the same as previously 
described. Each cell 38 is closed on one end and connected at the other 
end to a flexible tube 42 as indicated in FIG. 13. Connected to these 
tubes 42 is a manifold 50. A distribution means 52 which is like that 
described in U.S. Pat. No. 3,613,671, to Poor, et al sequentially 
distributes compressed air from inflatable means 54 (a source of 
compressed air). The distribution means 52 can be regulated to provide a 
sequencing of the pressure in the cells 38 to produce a transverse wave 
from the front of the seat to the rear only. This transverse wave improves 
the blood flow in the human body by forcing the blood from the legs toward 
the heart. 
Also preferably included in this embodiment are a pressure regulator 56 and 
rate sequencing means 58. 
Rate sequencing means 58 is preferably a rheostat which varies the imput 
power to the motor (not shown) driving the distribution means 52. This 
allows the user to vary both the intensity and rate of transverse wave 
travel to further alleviate discomfort from long sedentary positions. 
Thus, it is apparent that there has been provided, in accordance with the 
invention, a comfort support seat cushion that fully satisfies the 
objectives, aims, and advantages set forth above. While the invention has 
been described in conjunction with specific embodiments thereof, it is 
evident that many alternatives, modifications, and variations will be 
apparenrt to those skilled in the art in light of the foregoing 
description. Accordingly, it is intended to embrace all such alternatives, 
modifications, and variations which fall within the spirit and scope of 
the appended claims.