Semi-fluid based body support system

A semi-fluid based body support system using a mass of granular material to support a user has reversible transferring means and fluidizing means to locally control the granular material. The reversible transferring means and fluidizing means are independently controlled at plural locations along a system longitudinal dimension so that each region of the user body may be independently accommodated. The reversible transferring means is used to achieve fitness for natural posture by controlling a distribution of the accumulative height of granular material, and transfers the granular material between a transverse middle portion and transverse side portions of the system reversibly. The fluidizing means is used to achieve reduced partial oppression by controlling a local fluidity of the granular material. In a preferred embodiment, rotary blade devices, placed at spaced locations along the system longitudinal dimension, implement the fluidizing and transferring means by switching between operational modes. The rotary blade devices each include a shaft with blades that is rotatable reversibly. A shaft axis of rotation is oriented at an angle in the approximate range of 60.degree. to 120.degree. relative to a system longitudinal axis. The blades extend over a zone on the shaft, wherein: the length of the zone is larger than 25% of a system transverse dimension; and the zone is located within a complementary half of the system transverse dimension. Blades located within the same zone have the same screw direction. Blades located within mutually opposite transverse halves of the system have opposite screw directions.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
 Not Applicable.
 REFERENCE TO A MICROFICHE APPENDIX
 Not Applicable.
 BACKGROUND OF THE INVENTION
 This invention in general relates to a bed system. More particularly, this
 invention relates to a user support system for a bed, such as a mattress,
 which uses fluidizable granular material to support the user thereon.
 The quality of sleep is generally influenced by the features of the
 mattress. The characteristics of a mattress affect the health of the user
 during the course of long time intervals. Important characteristics of the
 mattress can be considered to include reduced partial oppression, fitness
 for natural posture, stability in holding the user and potential for good
 ventilation.
 In ordinary homes, water mattresses, air mattresses and gel mattresses are
 widely known as mattresses having a soft feel. Although these mattresses
 are simple in structure and are moderate in price, they have some problems
 which need to be overcome. These problems include several of:
 (a) partial oppression caused by the tension of a sealed container holding
 the fluid;
 (b) deterioration of supported posture, caused by a difference in weight
 (or specific gravity) of regions of the body;
 (c) low stability in holding the body, resulting from high fluidity of the
 fluid;
 (d) lack of ventilation, due to the use of the sealed container; and
 (e) thermal disharmony caused by a large thermal capacity of a mass of
 water.
 In the medical fields, fluidized beds are used for supporting the patient
 with little partial oppression. There are some problems associated with
 using fluidized beds in the home, including several of:
 (a) extra weight relating to buoyancy of the fluidized granular material;
 (b) extra energy consumed for thermal conditioning of the pressurized air;
 (c) deterioration of supported posture, caused by a difference in weight
 (or specific gravity) of regions of the body; and
 (d) unstable controllability in fluidizing the granular material, relating
 to the aerodynamics.
 With respect to fluidized beds, the Goodwin patent (U.S. Pat. No.
 4,637,083) discloses a fluidized patient support apparatus, the Eady
 patent (U.S. Pat. No. 4,951,335) discloses a mattress assembly, the Smith
 patent (U.S. Pat. No. 4,686,723) discloses a semi-fluidized bed, the Kato
 patent (U.S. Pat. No. 4,768,250) discloses a fluidized bead bed, the
 Romano patent (U.S. Pat. No. 5,539,943) discloses an apparatus and method
 for percussion of fluidized support surface and the Voelker patent (U.S.
 Pat. No. 3,840,920) discloses an adjustable mattress for pregnant mothers.
 BRIEF SUMMARY OF THE INVENTION
 It is an object of the present invention to provide a semi-fluid based body
 support system having reduced partial oppression, fitness for natural
 posture, stability in holding the user, potential for good ventilation and
 moderate (or relative) balance.
 It is another object of the present invention to provide a semi-fluid based
 body support system including relatively simple machinery which is
 suitable for the fine and firm control of the granular material and is
 also suitable for a home bed with a shallow and wide structure.
 It is another object of the present invention to provide a semi-fluid based
 body support system having reduced weight.
 The semi-fluid based body support system of this invention is suitable for
 a mattress and a bed. The semi-fluid based body support system is
 applicable to mattresses and beds in the medical fields where it is
 required to support a patient in reduced partial oppression. The patient
 or nurse can adjust this semi-fluid based body support system to fit the
 natural posture of the patient attained during sleep. This semi-fluid
 based body support system does not need the flow of pressurized air, so it
 is relatively easy to keep a bed warm. Furthermore, the mechanism of this
 semi-fluid based body support system can be embodied in a shallow and wide
 structure which is often used in a home bed. Therefore, this semi-fluid
 based body support system is especially suitable for a home mattress and a
 home bed in everyday life. Since this semi-fluid based body support system
 solves, to some extent, a conflict between reduced partial oppression and
 fitness for natural posture, this system has the potential of improving
 the quality of sleep in the home mattress and the home bed.
 The semi-fluid based body support system of this invention is also suitable
 for production using automatic machine tools because the main machinery of
 this system can be embodied by repetitions of relatively simple apparatus,
 such as a rotary blade device.
 The semi-fluid based body support system of this invention also gives a
 benefit of motive power to sleep because it can really apply powerful
 machinery to a mattress and a bed.
 Other features and advantages of this invention will be apparent from the
 detailed description of the invention, and from the claims.

DETAILED DESCRIPTION OF THE INVENTION
 FIGS. 1 through 11 illustrate the first preferred embodiment of a
 semi-fluid based body support system of this invention. The semi-fluid
 based body support system of this embodiment comprises a frame 33a-33b
 having a floor 39 and a wall 40a-40b, a mass of granular material 30 held
 (or disposed) in the frame 33a-33b, means for fluidizing the granular
 material 31a-31b and means for transferring the granular material 31a-31b,
 as illustrated in FIGS. 1, 2 and 3. The user is supported on the granular
 material 31a-31b through an air permeable sheet 34 which is connected to
 the wall 40a-40b of the frame 33a-33b.
 The frame 33a-33b is composed of a base frame 33a and a cushion frame 33b.
 The base frame 33a holds the machinery and fixes the hem of the air
 permeable sheet 34. The machinery is mainly composed of rotary blade
 devices 32a-32w, which are discussed below, and related components. The
 machinery drives the granular material 31a-31b finely and firmly to assist
 the user in obtaining an appropriate support condition in each region of
 his body. A safety net member 35 is placed over the machinery to protect
 the user from the machinery. A safety net member 35 is supported by the
 base frame 33a. The cushion frame 33b surrounds the air permeable sheet 34
 and provides a soft feel for the user. The term "floor of the frame" as
 used herein is intended to represent a member (or portion) of the frame
 33a-33b, which substantially forms a floor surface at a base portion of
 the frame 33a-33b. The term "wall of the frame" as used herein is intended
 to represent a member (or portion) of the frame 33a-33b, which
 substantially forms a wall surface at a side portion of the frame 33a-33b.
 The granular material 31a-31b, such as solid grains, beads, or the like,
 operates in a stationary state, in a grainy state and in a fluent state.
 The term "semi-fluid" as used herein is an alias of the granular material
 31a-31b based on its function.
 By nature, the semi-fluid based body support system of this embodiment has
 the potential for good ventilation passing through the granular material
 and has stability in holding the user due to low fluidity of the granular
 material in its stationary state.
 In order to obtain both reduced partial oppression and fitness for natural
 posture, the semi-fluid based body support system of this embodiment
 comprises:
 (1) means for fluidizing the granular material 31a-31b, wherein the
 fluidizing means independently controls the fluidizing of the granular
 material 31a-31b at more than one place along a longitudinal dimension 50
 of the frame 33a-33b; and
 (2) means for transferring the granular material 31a-31b between a
 transverse middle portion 54 and transverse side portions 55a and 55b of
 the frame 33a-33b, wherein: a transfer direction of the transferring means
 is reversible; and the transferring means independently controls the
 transferring of the granular material 31a-31b at more than one location
 along a longitudinal dimension 50 of the frame 33a-33b.
 The fluidizing means is used to reduce the partial oppression by locally
 fluidizing the granular material 31a-31b in the places corresponding to
 each region 51 of the user's body. Also, the transferring means is used to
 fit this semi-fluid based body support system to the natural posture of
 the user by adjusting an accumulative height 53 of the granular material
 31a-31b in the locations corresponding to each region 51 of a body. The
 above places and locations can overlap with each other.
 The transferring means functions as means for adjusting an accumulative
 height 53 of the granular material 31a-31b in the transverse middle
 portion 54 of the frame 33a-33b. Thus, in other words, the above-mentioned
 adjusting means independently controls the adjustment of the accumulative
 height 53 of the granular material 31a-31b at more than one location along
 the longitudinal dimension 50 of the frame 33a-33b.
 The term "partial oppression" as used herein is intended to represent the
 concentration of pressure in a narrow area on the surface of the body in
 supporting a user's weight, generally depending on the shape of the
 support surface of this semi-fluid based body support system. The term
 "reduced partial oppression" as used herein is intended to represent
 relatively reduced partial oppression in a general sense. The term
 "fitness for natural posture" as used herein is intended to represent the
 ability to fit this semi-fluid based body support system adaptively to a
 medically natural posture (or attitude) attained during sleep or to a
 posture desired by the user. As for a pressure distribution on the surface
 of the body, the reduction of the partial oppression corresponds to an
 equalization of the pressure in a local area, and fitness for the natural
 posture corresponds to a redistribution of the pressure in a global area.
 The fluidizing means and the transferring means can be realized under two
 kinds of apparatus. However, in this embodiment, to simplify the structure
 of the machinery, these means are realized under one kind of apparatus
 which is applicable to both means by changing its operational mode. This
 apparatus is a rotary blade device as called herein. In other words, the
 fluidizing means and the transferring means jointly comprise the rotary
 blade device.
 Plural rotary blade devices 32a-32w are supported by the frame 33a-33b as
 illustrated in FIGS. 1, 2 and 3. The rotary blade devices 32a-32w are
 located along the longitudinal dimension 50 of the frame 33a-33b, and
 preferably should be installed near the bottom of the frame 33a-33b in an
 array. Preferably, each of the rotary blade devices 32a-32w should be
 independently controlled so that each region of the user's body may be
 independently cared for.
 Each of the rotary blade devices 32a-32w includes:
 (a) a shaft member 42 rotatable on an axis of rotation 43 being oriented at
 an angle in the approximate range of 60.degree. to 120.degree., preferably
 from 80.degree. to 100.degree. and desirably 90.degree., relative to a
 longitudinal axis 37 of the frame 33a-33b, wherein the shaft member is
 rotatable reversibly; and
 (b) a blade member 60a connected to the shaft member 42.
 The term "shaft member" as used herein is intended to represent a member
 which translates rotatory power to the blade member 60a and has a simple
 or complex rod-like or pipe-like structure usually called a shaft. The
 term "blade member" as used herein is intended to represent a member which
 drives the granular material 31a-31b by rotating on the axis of rotation
 43 and has a simple or complex plate-like or blade-like structure usually
 called a blade, vane or fin.
 The rotary blade devices 32a-32w can include a sole blade (i.e. single
 blade) and/or a continuous blade, such as the blade member 60a. The blade
 member 60a can be directly connected to the shaft member 42, but also can
 be substantially connected to the shaft member 42 through a coupling, such
 as a clutch. Usually, the blade members are located at spaced locations on
 the shaft member 42. The rotary blade devices 32a-32w also can include an
 impeller member 44g composed of the blade members 60a-60d. The term
 "impeller member" as used herein is intended to represent a member which
 has an impeller-like or runner-like structure made by plural blade members
 60a-60d and is usually called an impeller, screw, fan or propeller.
 Each of the rotary blade devices 32a-32w includes left-handed impeller
 members 44a-44g and right-handed impeller members 45a-45g as illustrated
 in FIGS. 3, 5, 6 and 7. Each of the left-handed impeller members 44a-44g
 is composed of the blade members 60a-60d having a left-handed screw
 direction, and each of the right-handed impeller members 45a-45g is
 composed of the blade members 61a-61d having a right-handed screw
 direction.
 At this point, as illustrated in FIGS. 5 and 6, the frame 33a-33b defines a
 left zone 56 and a right zone 57 on the shaft member 42, wherein: the
 length of each of the left zone 56 and the right zone 57 is larger than
 25% of a transverse dimension 59 of the frame 33a-33b; and the left zone
 56 and the right zone 57 are located within complementary halves 58a and
 58b of the transverse dimension 59 of the frame 33a-33b, respectively.
 Each complementary half of the transverse dimension 59 of the frame 33a-33b
 corresponds to a space (or an extent) between a central longitudinal axis
 of the frame 33a-33b and a transverse side of the frame 33a-33b. Thus, for
 example, the left zone 56 is disposed between a central longitudinal axis
 of the frame 33a-33b and a transverse side of the frame 33a-33b, and
 length of the left zone 56 is larger than 25% of a transverse dimension of
 the frame 33a-33b.
 Preferably, placement of the blade members of the left-handed impeller
 members 44a-44g should extend over the left zone 56, while placement of
 the blade members of the right-handed impeller members 45a-45g should
 extend over the right zone 57.
 Preferably, the blade members of the left-handed impeller members 44a-44g
 located within the same zone 56 should have a uniform 63a (i.e. the same)
 screw direction 62a, and also the blade members of right-handed impeller
 members 45a-45g located within the same zone 57 should have a uniform 63b
 (i.e. the same) screw direction 62b. The directions 63a and 63b indicate
 screw directions 62a and 62b along the axis of rotation 43, respectively.
 Preferably, the blade members of the left-handed impeller members 44a-44g
 located within the left zone 56 and the blade members of the right-handed
 impeller members 45a-45g located within the right zone 57 should have
 opposite screw directions 62a and 62b when the left zone 56 and the right
 zone 57 are located within opposite complementary halves 58a and 58b of
 the transverse dimension 59 of the frame 33a-33b, respectively.
 Also preferably, the first blade member 60a and the second blade member 61a
 should have opposite screw directions with each other when they are
 located in opposite transverse half sides of the frame 33a-33b,
 respectively.
 The left zone 56 defines a blade union including all of the blade members
 of the left-handed impeller members 44a-44g located within the left zone
 56, and, preferably, the blade union should move the granular material
 passing through the left zone 56.
 Also, preferably, the blade members of the left-handed impeller members
 44a-44g located within the left zone 56 cooperate to move the granular
 material passing through the left zone 56 when the shaft member 42 is
 rotated about the axis of rotation 43.
 Instead of the transferring means defined in paragraph (2) above, the
 semi-fluid based body support system of this embodiment can include the
 transferring means defined in a different manner, including:
 (2A) means for transferring the granular material 31a-31b at an angle in
 the approximate range of 60.degree. to 120.degree. relative to the
 longitudinal axis 37 of the frame 33a-33b, wherein: the granular material
 31a-31b are transferred in opposite transverse directions when they are
 located within opposite transverse half sides of the frame 33a-33b,
 respectively; the transfer direction of the transferring means is
 reversible; and the transferring means independently controls the
 transferring of the granular material 31a-31b at more than one location
 along the longitudinal dimension 50 of the frame 33a-33b; and
 (2B) means for transferring the granular material 31a-31b at an angle in
 the approximate range of 60.degree. to 120.degree. relative to the
 longitudinal axis 37 of the frame 33a-33b, wherein: a first granular
 material is transferred passing through the left zone 56 and a second
 granular material is transferred passing through the right zone 57; the
 transfer direction of the transferring means is reversible; and the
 transferring means independently controls the transferring of the granular
 material 31a-31b at more than one location along the longitudinal
 dimension 50 of the frame 33a-33b.
 FIG. 7 illustrates the granular material 31c and 31d around the shaft
 member 42 and the left-handed impeller member 44f. Preferably, the blade
 area of the blade members 60a-60h should be much larger than the size of
 the granular material 31c and 31d.
 Preferably, each of the rotary blade devices 32a-32w should further include
 means for rotating the shaft member 42 reversibly, as illustrated in FIGS.
 3 and 5. Preferably, the rotating means should include a driving motor 41
 connected to the shaft member 42.
 The driving motor 41 rotates the left-handed impeller members 44a-44g and
 right-handed impeller members 45a-45g clockwise, counterclockwise and
 alternately clockwise and counterclockwise, through the shaft member 42.
 The alternate rotation of the impeller members 44a-44g and 45a-45g
 includes unbalanced rotation such as, for example, turning twice clockwise
 after turning once counterclockwise. Operation of each of the rotary blade
 devices 32a-32w is independently controlled, by the user, including the
 following operations: starting, stopping, direction of rotation and,
 preferably, speed of revolution. The user would be able to use some kind
 of remote control apparatus for controlling the rotary blade devices
 32a-32w.
 Each of the rotary blade devices 32a-32w is fixed to the base frame 33a by
 the bearing 46, seals 47a-47b and flange 48 of the driving motor 41 so
 that the shaft member 42 may be supported in the frame 33a-33b so as to be
 rotatable on the axis of rotation 43. Preferably, the rotary blade devices
 32a-32w should be prepared severally (e.g., in groups) for each main
 region of the body including a head, shoulder, waist, hip, thigh and foot.
 Each installing space between the adjoining rotary blade devices 32a, 32b
 can be varied.
 Preferably, to protect the machinery from a surge strain caused by the
 local pressure in the semi-fluid based body support system of this
 embodiment, a main portion of the shaft member 42 and the impeller members
 44a-44g and 45a-45g should have a resilient structure or should be formed
 using elastic material such as a hard rubber component. Preferably, the
 mesh size of the safety net member 35 should be much larger than the size
 of the granular material 31a-31b so that the moving of the granular
 material 31a-31b may not be obstructed by the safety net member 35. The
 safety net member 35 covers the blade members of the impeller members
 44a-44g and 45a-45g.
 Preferably, the air permeable sheet 34 should have little tension and a big
 leeway to reject partial oppression caused by the tension of the air
 permeable sheet 34, as shown by wrinkles 36 illustrated in FIG. 1. If
 ventilation through the granular material 31a-31b is not important, an air
 impermeable sheet can be used instead of the air permeable sheet 34, and
 the granular material can be lubricated.
 The term "fluidizing the granular material" as used herein is intended to
 represent flowing (or drifting) the granular material 31a-31b so that they
 may have some fluidity.
 The term "transferring the granular material" as used herein is intended to
 represent moving (or transferring) the granular material so that the
 granular material may move from the departing location to the destination
 within the semi-fluid based body support system of this embodiment.
 The term "accumulative height of the granular material" as used herein is
 intended to represent the vertical thickness of a mass of granular
 material 30 accumulated (or disposed) in the semi-fluid based body support
 system of this embodiment, at the point of measurement.
 The term "transverse middle portion of the frame" as used herein is
 intended to represent generally a transverse portion of the frame 33a-33b,
 for supporting the user thereon. Usually, the user is supported in a
 middle portion of the frame. Therefore, generally, the term "transverse
 middle portion of the frame" as used herein is intended to represent a
 portion of the frame 33a-33b, wherein: a transverse dimension (i.e. a
 dimension measured in a transverse direction of the frame 33a-33b) of the
 portion is from 10% to 50%, preferably 20% to 40%, of the transverse
 dimension 59 of the frame 33a-33b; and the transverse center (i.e. a
 center measured in a transverse direction of the frame 33a-33b) of the
 portion is identical with the transverse center of the frame 33a-33b. The
 above-mentioned portion of the frame 33a-33b includes the space above the
 floor 39 of the frame 33a-33b, where the granular material resides.
 The term "transverse side portion of the frame" as used herein is intended
 to represent either of the rest portions of the transverse middle portion
 of the frame.
 Reduced Partial Oppression
 To reduce the partial oppression, the semi-fluid based body support system
 of this embodiment operates the rotary blade devices 32a-32w in a
 fluidizing mode as called herein so that the impeller members 44a-44g and
 45a-45g may rotate alternately clockwise and counterclockwise as shown by
 an arrow 65, as illustrated in FIGS. 6 and 8A. The granular material 31e
 and 31f around the impeller members 44a-44g and 45a-45g is shaken (or
 stirred) as shown schematically by arrows 66a and 66b and gets local
 fluidity depending on the output power of the driving motor 41.
 As illustrated in FIG. 9A, if the user (head 71a, shoulder 71b, waist 71c,
 hip 71d, and leg 71e) feels the partial oppression at his leg region 71e
 in a current support condition 72, the user operates rotary blade devices
 32o-32t, which correspond to leg region 71e, in the fluidizing mode. The
 driven granular material 31k and 31L in an area 74 around the rotary blade
 devices 32o-32t flows (or drifts) locally, like a fluid, in the semi-fluid
 based body support system of this embodiment, and the shape of this
 semi-fluid based body support system contacting the body changes to a new
 shape with reduced partial oppression at that area 74, due to the
 characteristics of the fluid. Thus, the user obtains a new support
 condition 73 with reduced partial oppression at the leg region 71e.
 Within a period of the above operation, the granular material still remains
 in a stationary state at the surrounding area 75a and 75b of the other
 rotary blade devices 32a-32n and 32u-32w which are stationary or stopped.
 In the stationary state, since a mass of granular material 30 can support
 a load steadily in the shape presented, the other regions 71a-71d of the
 body continue to be supported steadily on the granular material while the
 above operation continues.
 When the user gains a feeling of satisfaction about the partial oppression,
 the user stops all of the rotary blade devices 32a-32w. The semi-fluid
 based body support system of this embodiment thereafter supports the user
 steadily in the shape presented at the time of disabling the rotary blade
 devices. Thus, the semi-fluid based body support system of this embodiment
 can continue to support the body steadily in reduced partial oppression,
 if this semi-fluid based body support system has such a shape
 corresponding to reduced partial oppression, obtained through
 above-mentioned operation.
 Fitness for Natural Posture
 To fit the semi-fluid based body support system of this embodiment to the
 natural posture of the user, the semi-fluid based body support system of
 this embodiment operates the rotary blade devices 32a-32w in a
 transferring mode as called herein so that the impeller members 44a-44g
 and 45a-45g may rotate in a certain direction as shown by an arrow 67 or
 69, as illustrated in FIGS. 8B and 8C. Because of a difference in weight
 (or specific gravity) of regions of the body, the user tends to have an
 unnatural posture when lying on a fluid or fluidized bed.
 To compensate for deterioration of the posture, it is important to adjust a
 supporting height 52 for each region 51 of the body. As illustrated in
 FIG. 5, in the semi-fluid based body support system of this embodiment,
 the adjustment of the supporting height 52 is achieved by transferring the
 granular material 31 a between a transverse middle portion 54 and
 transverse side portions 55a and 55b of the frame 33a-33b.
 Since each of the rotary blade devices 32a-32w has the left-handed impeller
 members 44a-44g located within the left zone 56 and the right-handed
 impeller members 45a-45g located within the right zone 57 as illustrated
 in FIGS. 5, 6 and 8C, the granular material 31i and 31j around the
 impeller members 44a-44g and 45a-45g is transferred from the transverse
 middle portion 54 to the transverse side portions 55a and 55b of the frame
 33a-33b as shown schematically by arrows 70a and 70b when the impeller
 members 44a-44g and 45a-45g rotate clockwise viewing from the driving
 motor 41 as shown by an arrow 69.
 By contrast, when the impeller members 44a-44g and 45a-45g rotate
 counterclockwise viewing from the driving motor 41 as shown by arrow 67 as
 illustrated in FIGS. 6 and 8B, the granular material 31g and 31h around
 the impeller members 44a-44g and 45a-45g is transferred from the
 transverse side portions 55a and 55b to the transverse middle portion 54
 of the frame 33a-33b as shown schematically by arrows 68a and 68b.
 The above-mentioned transferring of the granular material makes it possible
 to adjust the distribution of an accumulative height 53 of the granular
 material in the transverse middle portion 54 of the frame 33a-33b.
 By independently controlling the rotary blade devices 32a-32w which are
 located along the longitudinal dimension 50 of the frame 33a-33b, it
 becomes possible to adjust a distribution of the accumulative height 53 of
 the granular material along the longitudinal dimension 50 of the frame
 33a-33b at the transverse middle portion 54 of the frame 33a-33b. Since
 the transverse middle portion 54 of the frame 33a-33b generally
 corresponds to an area for supporting the user thereon, the
 above-mentioned adjustment of the granular material corresponds to an
 adjustment of the supporting height 52 in each region 51 of the body.
 If the user feels something wrong, in the current posture 81 or 85, about
 the supporting height in his hip region 71d, the user operates a part of
 the rotary blade devices 32L corresponding to the hip region 71d in the
 transferring mode, as illustrated in FIGS. 10A, 10B and 9B.
 FIG. 10A illustrates a case of lifting the hip region 71d from the current
 supporting height 82 to new supporting height 83 by transferring the
 granular material 31n and 31o from the transverse side portions 55a and
 55b to the transverse middle portion 54 of the frame 33a-33b, as shown
 schematically by arrows 84a and 84b, by rotating the impeller members
 44a-44g and 45a-45g of the rotary blade device 32L counterclockwise as
 shown by an arrow 67.
 FIG. 10B illustrates a case of sinking down (or lowering) the hip region
 71d from the current supporting height 86 to new supporting height 87 by
 transferring the granular material 31p and 31q from the transverse middle
 portion 54 to the transverse side portions 55a and 55b of the frame
 33a-33b, as shown schematically by arrows 88a and 88b, by rotating the
 impeller members 44a-44g and 45a-45g of the rotary blade device 32L
 clockwise as shown by an arrow 69.
 Thus, by applying the above-mentioned operation to each region of the body,
 the semi-fluid based body support system of this embodiment obtains
 fitness for natural posture.
 Light Granular Material
 In order to reduce the weight of the semi-fluid based body support system
 of this embodiment, it is appropriate to use light granular material. If
 the light granular material is used, the user tends to sink in this
 semi-fluid based body support system when the granular material is
 fluidized widely because the buoyancy operating on the body is
 insufficient to support the body.
 A scanning control method, as called herein, of the rotary blade devices
 32a-32w provides a narrow fluidized area of the granular material and a
 wide stationary area of the granular material before and behind the narrow
 fluidized area. The control method scans the narrow fluidized area along
 the body while supporting the user steadily on the wide stationary area.
 As illustrated in FIG. 9B, if the user feels the partial oppression at all
 regions 71a-71e in the current support condition 76, the user needs to
 operate rotary blade devices 32c-32t corresponding to regions 71a-71e, in
 the fluidizing mode. In this case, if all of the above rotary blade
 devices 32c-32t are operated at a time, it is inevitable that the user
 suffers severe deterioration of posture caused by sinking of the whole
 body into the light granular material.
 Accordingly, the user operates the required rotary blade devices 32c-32t
 one by one in turn, as shown by an arrow 80. In a narrow fluidized area 78
 corresponding to the rotary blade device 32L which is operated currently,
 the shape of the semi-fluid based body support system of this embodiment
 changes to a new shape with reduced partial oppression by the flow of the
 granular material. Also, in the wide stationary areas 79a and 79b
 corresponding to the rotary blade devices 32a-32k and 32m-32w which are
 paused currently, the other regions of the body are supported steadily on
 the granular material. By scanning the narrow fluidized area 78 along all
 regions, the user obtains reduced partial oppression on the whole body at
 new support condition 77 without suffering severe deterioration of the
 posture.
 By applying the scanning control method of the rotary blade devices 32a-32w
 to the operations in the fluidizing mode and in the transferring mode, the
 semi-fluid based body support system of this embodiment provides the user
 with a totally desirable effect on all of the regions while preventing the
 body from over sinking, even if a light granular material is used.
 In the case of using a light granular material, preferably, the rotary
 blade devices should be rotated intermittently (or with periodical pulsed
 driving), especially when transferring the granular material. By the
 intermittent rotation of the rotary blade devices, the shortage of
 buoyancy is compensated to some extent due to the inertia of the body and
 granular material and some stability in an arrangement of a mass of
 granular material 30. In addition, the scanning control method of the
 rotary blade devices is also applicable to the case of using heavy
 granular material.
 Mixture of Operation
 In the above description, the operation for obtaining reduced partial
 oppression and the operation for obtaining fitness for natural posture are
 explained separately. But it is important to simultaneously apply these
 operations to the rotary blade devices 32a-32w to obtain reduced partial
 oppression and fitness for natural posture, moderately balanced.
 Preferably, these operations should be applied to each region of the body
 jointly, repeatedly and little by little, using an unbalanced rotation of
 the rotary blade devices 32a-32w, such as turning twice clockwise after
 turning once counterclockwise. The above unbalanced rotation of the rotary
 blade devices 32a-32w has a mixed effect on the operations of fluidizing
 and transferring the granular material. Thus, the user obtains reduced
 partial oppression and fitness for natural posture.
 Installation to Bed
 The semi-fluid based body support system of this embodiment can be
 installed in a bed so as to be separable or inseparable from the bed. FIG.
 11 illustrates a bed mainly composed of the semi-fluid based body support
 system of this embodiment, a power control unit 89, a power line 90 and
 legs 91. The power control unit 89 is connected to the power line 90 and
 drives the rotary blade devices 32a-32w under the control of the user,
 preferably through some kind of remote control apparatus. The power
 control unit 89 can be composed mainly of an electronic circuit and heat
 sinks. In this case, the semi-fluid based body support system of this
 embodiment can have the power control unit 89 built-in by installing the
 heat sinks, for example, in the bottom face of the floor 39 of the frame
 33a-33b.
 Channel Structure
 FIGS. 12 through 15 illustrate the second preferred embodiment of a
 semi-fluid based body support system of this invention. This embodiment
 further comprises a channel structure (or groove structure) in addition to
 being constructed like the first preferred embodiment, in order to
 localize the function area of the rotary blade devices 32a-32w and to
 strengthen the mechanical structure. The channel structure is composed of
 channels 100a-100w generally arranged in parallel. The term "channel" as
 used herein is intended to represent a linear area of relatively deep
 portions.
 The floor 39 of the frame 33a-33b has channels 100a-100w formed on a top
 face of the floor 39, as illustrated in FIGS. 12 and 13. The channel 100a
 houses (or receives) the corresponding rotary blade device 32a at least
 partially. Thus the channel 100a is oriented at an angle in the
 approximate range of 60.degree. to 120.degree. relative to the
 longitudinal axis 37 of the frame 33a-33b, and the channels 100a-100w are
 located, preferably arranged, along the longitudinal dimension 50 of the
 frame 33a-33b. The shaft member 42 of the rotary blade device 32a is
 rotatable on the axis of rotation 43 generally parallel to the
 corresponding channel 100a.
 Preferably, every channel 100a-100w should support the safety net member 35
 to improve the strength of the safety net member 35. By connecting the
 safety net member 35 to the walls 101u and 101v of the channel 100v, it is
 possible to release the load on the safety net member 35 and it also
 becomes easy to cover the blade member of the rotary blade device 32v by
 the safety net member 35 to protect the user.
 Preferably, the vertical depth 170a, 170b and 170c of the channels 100c,
 100x and 100y should be equal to or greater than an external radius of
 rotation 103R (i.e. half of the external diameter, shown with a circle
 103) of the blade member of the impeller members 44g of the rotary blade
 devices 32c, as illustrated in FIGS. 14A, 14B, 14C and 14D. Since the wall
 101a of the channel 100a controls the longitudinal moving of the granular
 material 31r toward the next channel 100b as illustrated in FIG. 13, the
 function area of the rotary blade device 32a is localized, so that the
 independent controllability in each region of the body is improved.
 The height of the walls 101a-101v and 101x-101z of the channels can vary
 severally depending on the characteristics of the granular material and/or
 on the regions of the body, as illustrated in FIGS. 13, 14A and 14B. Also,
 two or more rotary blade devices 32c and 32d can be placed in the same
 channel 100x, as illustrated in FIG. 14B. As illustrated in FIG. 14C, the
 function areas of the adjoining rotary blade devices 32c and 32d placed in
 the same channel 100y can overlap with each other by shifting the mounting
 positions of the impeller members on the shaft member 42.
 As illustrated in FIG. 14D, in order to support the rotary blade device 32c
 when the shaft member 42 is deflected by a lateral load, preferably, the
 inner surface of the channel 100c should share the lateral load like a
 bearing for the impeller member 44g. Therefore, preferably, the radius of
 curvature 102R (i.e. half of the core diameter, shown with a circle 102)
 of the inner surface of the channel 100c should be substantially equal to
 an external radius of rotation 103R of the impeller members 44a-44g and
 45a-45g at least in its bottom portion. Normally, the rotary blade device
 32c is apart from the inner surface of the channel 100c. They contact when
 the shaft member 42 is deflected, and the inner surface of the channel
 100c supports the rotary blade device 32c. Lateral load is also
 supportable by using ordinary bearings for extra support of the shaft
 member 42.
 A direction of a channel can be curved or bent, if necessary. In the curved
 channel, divided shaft members, flexible joints and extra bearings for the
 shaft member are available for the rotary blade device.
 As illustrated in FIG. 15, the channel structure having channels 100b-100e
 can be also formed by partitions 104a-104e supported in the frame 33a-33b.
 The partition 104a functions like the wall 101a of channels 100a and 100b.
 The partitions 104a-104e are fixed to the floor 39 of the frame 33a-33b by
 the bolts 105.
 The partition 104b is located between the adjoining rotary blade devices
 32b and 32c. Thus, the partitions 104a-104e are oriented at an angle in
 the approximate range of 60.degree. to 120.degree. relative to the
 longitudinal axis 37 of the frame 33a-33b and are located, preferably
 arranged, along the longitudinal dimension 50 of the frame 33a-33b. The
 shaft member 42 of the rotary blade device 32a is rotatable on the axis of
 rotation 43 generally parallel to the direction of the corresponding
 partition 104b. The partition 104d can have holes, if necessary.
 Preferably, the vertical height of the partition 104b should be equal to or
 greater than an external radius of rotation 103R of the blade member of
 the impeller members 44a-44g and 45a-45g. The vertical height of the
 partition 104b, as used herein, is defined as a height of the top of the
 partition 104b measured from the bottom of the impeller members of the
 rotary blade devices 32b and 32c.
 Cell Structure
 FIGS. 16 through 18 illustrate the third preferred embodiment of a
 semi-fluid based body support system of this invention. This embodiment
 comprises a cell structure in addition to being constructed like the
 second preferred embodiment, to lessen the trouble in making a bed (e.g.,
 provide a more rapid adjustment of the system to the user) and to improve
 the feel of this semi-fluid based body support system. The cell structure
 is composed of cells 110a-110d arranged in the frame 33a-33b
 longitudinally.
 As illustrated in FIGS. 17A and 17B, the frame 33a-33b and the air
 permeable sheet 34 are further connected to the wall 101e of the channel
 100e and define a cell 110a surrounded thereby. Each of the cells
 110a-110d holds a part of a mass of granular material 30. Since a
 longitudinal migration (or drift) of the granular material 31s is
 restricted to inside of the cell 110a, it lessens the trouble in making a
 bed (e.g., the system may be rapidly adjusted to a user) which is usually
 required in the advance of medical preparations or in the turning of the
 body. The characteristics of the granular material held in each of the
 cells 110a-110d can vary severally to improve the feel of this semi-fluid
 based body support system.
 As illustrated in FIG. 18, the partitions 104a-104e supported in the frame
 33a-33b can be used for the cell structure. In this case, the frame
 33a-33b and the air permeable sheet 34 are connected to the partitions
 104b and 104d and define a cell 110g surrounded thereby. Each of the cells
 110e-110h holds a part of a mass of granular material 30. One or more
 rotary blade devices 32c and 32d can be placed within the cell 110g. Also,
 the adjoining cells 110g and 110h can be connected through the holes of
 the partition 104d.
 Single-Ended Rotary Blade Device
 FIGS. 19A and 19B illustrate the fourth preferred embodiment of a
 semi-fluid based body support system of this invention. This embodiment
 comprises single-ended rotary blade devices 115a and 115b instead of the
 rotary blade devices 32a-32w of the first preferred embodiment.
 Each of the single-ended rotary blade devices 115a and 115b includes a
 shaft member 117 and right-handed impeller members 118a-118g connected to
 the shaft member 117, as illustrated in FIG. 19B. The driving motor 116 is
 connected to the shaft member 117 so as to rotate the right-handed
 impeller members 118a-118g clockwise, counterclockwise, and alternately
 clockwise and counterclockwise. Operation of each of the single-ended
 rotary blade devices 115a and 115b is independently controlled, by the
 user, including the following operations: starting, stopping, direction of
 rotation and, preferably, speed of revolution. The single-ended rotary
 blade devices 115a and 115b are installed in the frame 33a so that an axis
 of rotation 119a and 119b of the shaft member 117 may be oriented at an
 angle in the approximate range of 60.degree. to 120.degree. relative to a
 longitudinal axis 37 of the frame 33a. Preferably, the single-ended rotary
 blade devices 115a and 115b face each other and should be used as a pair.
 The vertical directions of the axes of rotation 119a and 119b of the
 single-ended rotary blade devices 115a and 115b can vary with each other,
 as illustrated in FIG. 19A. Also, the horizontal directions of the axes of
 rotation 119a and 119b of the single-ended rotary blade devices 115a and
 115b can vary with each other.
 The operations of the single-ended rotary blade devices 115a and 115b are
 similar to those of the rotary blade devices 32a-32w in the first
 preferred embodiment. For example, clockwise rotation of the rotary blade
 devices 32a-32w in the first preferred embodiment corresponds to the same
 clockwise rotation of the single-ended rotary blade devices 115a and 115b.
 Each of the rotary blade devices 32a-32w in the first preferred embodiment
 include left-handed impeller members 44a-44g located within the left zone
 56 and right-handed impeller members 45a-45g located within the right zone
 57, while the single-ended rotary blade devices 115a and 115b include
 right-handed impeller members 118a-118g located within left zone 56 and
 right zone 57, respectively. The user can improve the handling of this
 semi-fluid based body support system by driving each of the single-ended
 rotary blade devices 115a and 115b independently.
 A pair of the single-ended rotary blade devices 115a and 115b, facing each
 other transversely, can be connected by a flexible joint and be driven by
 a common driving motor, if the screw directions of their impeller members
 (i.e. screw direction in left zone 56 and screw direction in right zone
 57) are opposite each other. The rotary blade devices 32a-32w of the first
 preferred embodiment can be divided into three or more pieces, if
 necessary.
 Blade and Guide
 FIGS. 20A, 20B, 20C and 21 illustrate the other preferred embodiments of
 the rotary blade device and related components. Although the rotary blade
 devices 32a-32w are applied to both of the fluidizing means and the
 transferring means, each blade member of the rotary blade devices 32a-32w
 can have a biased feature suitable for either fluidizing means or
 transferring means. Therefore, the blade shape, blade area, blade angle,
 blade inclination, blade eccentricity and blade linkage can vary in every
 blade member.
 FIG. 20A illustrates a rotary blade device 120 having left-handed inclined
 impeller members 121a-121e and right-handed inclined impeller members
 122a-122e so as to have mixed effects in fluidizing and transferring the
 granular material 31a-31b.
 FIG. 20B illustrates a rotary blade device 123 having left-handed inclined
 and eccentric sole blade members 124a-124f and right-handed inclined and
 eccentric sole blade members 125a-125f so as to strengthen the effect in
 fluidizing the granular material 31a-31b.
 FIG. 20C illustrates a rotary blade device 126 having left-handed impeller
 members 127a-127g and right-handed impeller members 128a-128g, wherein the
 blade angle of the inner impeller member 127e (i.e. impeller member
 located at an inner position on the shaft member 42) is larger than the
 blade angle of the outer impeller member 127d. The transportable quantity
 129b of the inner impeller member 127e with a relatively large blade angle
 is larger than the transportable quantity 129a of the outer impeller
 member 127d with a relatively small blade angle. Thus, distributions of
 quantities of the granular material carried out or carried in within the
 transverse side portions 55a and 55b of the frame 33a-33b can be made
 relatively uniform due to the movement of granular material pushed out
 from, or drawn into, the array of the impeller members 127a-127g and
 128a-128g, as shown by arrows 130.
 A particularly shaped blade member partially including the above-mentioned
 features is available, if necessary. An example of such a particularly
 shaped blade member is a screw-like transferring blade partially having a
 kneading blade thereon. FIG. 20D illustrates a rotary blade device 131
 having a continuous screw blade member 132 as a simple example of the
 particularly shaped blade member.
 As illustrated in FIG. 21, preferably, a guide slope 133 should be used in
 the transverse center of the frame 33a-33b, to assist the function of the
 blade members.
 Mirror Symmetrical Arrangement
 FIGS. 22, 23A, 23B and 24 illustrate another preferred embodiment of
 arrangements of the rotary blade devices and its blade members. If many
 rotary blade devices 140a-140c and 141a-141c rotate in the same direction,
 the granular material 31t located above the channel 100b tends to migrate
 (or drift) in a longitudinal direction 37x of the frame 33a-33b because
 the granular material 31t is pushed in that direction 37x continuously by
 the blade members 142 and 143, as illustrated in FIG. 22.
 To compensate for the above migration, the adjoining rotary blade devices
 140a and 141a have substantially mirror symmetrical screw directions with
 each other in the longitudinal direction 37x of the frame 33a-33b, in an
 arrangement of their blade members 142 and 143. These adjoining
 longitudinally mirror symmetrical rotary blade devices 140a and 141a as
 called herein can be placed in the same channel as a pair of rotary blade
 devices, as similarly illustrated in FIG. 14B.
 As illustrated in FIG. 23A, when the adjoining longitudinally mirror
 symmetrical rotary blade devices 140a and 141a transfer the granular
 material 31t from the transverse middle portion 54 to the transverse side
 portion 55b of the frame 33a-33b (or reversibly) as shown by arrows 145a
 and 145b, these adjoining rotary blade devices 140a and 141a rotate in
 opposite directions with each other as shown by arrows 69 and 67.
 Therefore, the longitudinal migration of the granular material 31t is
 canceled to some extent as shown by arrows 146a and 146b.
 By contrast, when the adjoining longitudinally mirror symmetrical rotary
 blade devices 140a and 141a rotate in the same direction as shown by an
 arrow 69, the granular material 31t circulates relatively transversely as
 shown by arrows 145a and 145c and migrates longitudinally as shown by
 arrows 146a and 146c as illustrated in FIG. 23B. In this case, the
 longitudinal migration of the granular material 31t is intensified.
 Canceling or intensifying of the longitudinal migration of the granular
 material lessens further the trouble in making a bed (e.g., accelerates
 the rate of adjustment of the system to a user).
 FIG. 24 illustrates adjoining longitudinally mirror symmetrical rotary
 blade devices 150 and 151, wherein the blade angle of the inner impeller
 member of these rotary blade devices 150 and 151 is larger than the blade
 angle of the outer impeller member of these devices, as similarly
 illustrated in FIG. 20C. When these rotary blade devices 150 and 151 are
 rotated in the same direction as shown by an arrow 67, the granular
 material 31u tends to swirl between the adjoining rotary blade devices 150
 and 151 as shown by arrows 154a-154d and 155 since the transportable
 quantity of the blade members 153a and 153b are different. Thus, the
 effect in fluidizing the granular material is improved.
 Granular Material
 Preferably, the granular material should have low specific heat and low
 thermal conductivity to reduce the thermal disharmony. Preferably, the
 granular material should have sizes ranging from 1 millimeter (mm) to 3
 millimeters (mm) to provide the strength, feel and ventilation.
 Preferably, the granular material should be hard and slippery. Preferably,
 the granular material should have a variety of shapes and sizes so that a
 mass of granular material 30 may have appropriate stability or instability
 in an arrangement thereof.
 Furthermore, desirably, the granular material should have a little
 elasticity so as to follow slight movements of the user, such as
 breathing.
 A synthetic resin is applicable to the granular material to simplify its
 production. The hollow structured granular material is used to reduce the
 weight of this semi-fluid based body support system.
 Ventilation for Airlines
 FIGS. 25A and 25B schematically illustrate a preferred embodiment of an air
 circulating apparatus for a semi-fluid based body support system of this
 invention. The air circulating apparatus mainly circulates the air
 transversely through this semi-fluid based body support system.
 An air pump 160 having an intake port 162 and an outlet port 161 is
 installed in the frame 33a-33b, as illustrated in FIG. 25B. An inhaling
 duct 163 and an exhaling duct 164 are placed along the channel 100b, and
 are preferably formed within a wall 101b of the channel 100b. The inhaling
 duct 163 and the exhaling duct 164 are connected to the intake port 162
 and the outlet port 161 of the air pump 160, respectively. Air permeable
 inhaling holes 166, 166a and 166b are placed on the inhaling duct 163 and
 air permeable exhaling holes 165 are placed on the exhaling duct 164. The
 air permeable inhaling holes 166, 166a and 166b and the air permeable
 exhaling holes 165 are exposed to the granular material 31a respectively.
 To make the air currents 167a and 167b transversely circulate through the
 air permeable sheet 34 and the granular material 31a, the air permeable
 inhaling holes 166, 166a and 166b are located in the transverse side
 portions of the frame 33a-33b and the air permeable exhaling holes 165 are
 located in the transverse middle portion of the frame 33a-33b, as
 illustrated in FIG. 25B.
 By driving the air pump 160, the user obtains good ventilation by the air
 currents 167a and 167b which circulate from the back of the user to both
 sides of this semi-fluid based body support system transversely. Instead
 of the air permeable sheet 34, an air impermeable sheet with an air
 permeable area in its middle portion is available to keep the air warm by
 suppressing air leakage from the sheet side portions while the air
 circulates.
 It should also be understood that the foregoing relates to only preferred
 embodiments of the invention, and that it is intended to cover all changes
 and modifications of the examples of the invention herein chosen for the
 purpose of the disclosure, which do not constitute departures from the
 spirit and scope of the invention.