GB2209464A - Multi-positional bed: control arrangement - Google Patents

Abstract

A bed 10 comprises a generally rectangular base frame 12 to which is secured three supporting posts P1 to P3 at respective corners of base frame 12 and which carry a moveable upper frame 25. Each support post houses a drive mechanism for controlling the position of upper frame 25 in height, and in roll and pitch about axes parallel to the bed length and width respectively. The frame 25 may support a multi-section mattress 81, 82, 83, 84. <IMAGE>

Description

MULTI-POSITIONAL BED The present invention generally relates to a bed and more particularly to a bed with control means to control independently, each section of a plurality of sections of a patient-supporting mattress or the like, which is supported by a frame as well as to control the orientation of the frame about several axes.

There are many beds which have been developed to increase the comfort of bed-ridden people. Considering a bed mattress or the box spring on which it rests as consisting of several sections from the upper end GoWmwar as a back section, a buttocks section, a thigh section and a leg section, beds exist in which several of these sections can be tilted with respect to the others. Typically1 the buttocks section is fixed to the frame on which the mattress is supported This frame can be raised or lowered for patient comfort. Few, if any, of these special purpose beds enable the pitching and or rolling of the mattress, which is highly desirable for various treatments as well as routine sheet replacement.

None of the special purpose beds which have been investigated is so designed that it can be easily convertible into effectively a large chair. Such capability would enable many patients te get off or on their beds without aid which is at a critical shortage these days. To achieve this end the bed must be uniquely designed both in terms of frame design as well as the design of the multisectional mattress and the capabilities of its sections to be tilted properly. Clearly, the more controllable features a bed has, more controls are required. As far as a bed-ridden patient is concerned, one wishes to minimize the number of controls. It is to achieve these goals that the present invention is directed.The present invention may be defined as a controllable bed comprising: First means including a rigid base frame: and means for supporting said frame above the floor; a plurality of post means fixedly vertically -supported at corners of said base frame; command responsive drive means in at least some of said post means responsive to control signals for imparting rotational motion in each of at least some of said post means; an upper frame above said base frame for supporting a mattress thereon; and coupling means for coupling said upper frame to the drive means in at least some of said posts to control the orientation of said frame about three orthogonal axes.

In a preferred embodiment of the invention, although four posts are supported by the bottom base frame, drive means are associated and included in only three posts, two of which form the ends of the bed's headboard, and one forming the rer post of the footboard.

The upper frame is coupled to the drive means in the three posts so that the frame, on which the mattress is supported, can be raised or lowered, pitched and rolled, all his with three controllable motors. Three additional controllable motors with appropriate acutations and linking arms enable each of three separate mattress sections such as the back section, the thigh section and the leg section to assume any one of many desired positions. These sections can be controlled to assume the overall shape of a chair from.

which the patient can get up and walk away from the bed, without assistance.

By sending appropriate signals to one or more of the six motors, both the mattress contour and the orientation of the upper frame on which it is supported are easily controllable.

The novel features of the invention are set forth with particularity in the appended claims. The invention will best be understood from the following description when read in conjunction with the accompanying drawings.

Fig. 1 is an isometric view of one embodiment of the novel bed; Fig. 2 is a simple cross-sectional view of part of the mechanism employed in each of three posts of the bed to control the orientation of upper frame 25, shown in Fig. 1 Fig. 3 is a kinematic diagram of the mechanisms for supporting the upper frame; Figs. 4a and 4b are simplified diagrams useful in explaining the mattress conversion into a chair; Figs. 5a-Se are various diagrams of the mattress in different positions, both acceptable and unacceptable; Fig. 6 is essentially a combination crosssectional and block diagram of an actuator 100 generally used in the electromechanical mechanism, used to control each mattress section;; Figs 7-9 are diagrams of electromechanical mechanisms for controlling different mattress sections; Fig 10 is a diagram of part of the coupling mechanism which couples post P3 to the upper frame; Fig. 11 is a simplified diagram oz an arrangement for computer controlling the novel bed.

Attention is now directed to Fig. 1 in connection with which some of the basic features of the invention will be described Basically the novel bed 10 consists of a lower base frame 12 supported on wheels 13 for purpose of enabling the bed to be supported slightly above the floor and to be rolled on it The frame 12 acts as the bed's mai structural base and except for being moveable on wheels it is stationary. It is used to fixedly support, vertically, four posts designated P1 - P4, where P1 and P3 are at the head of the bed.They, together with a panel 15 connected thereto and a decorative upper bar 16 form the bed's headboard 20h A footboard 20f is formed b posts P2 and P4 which are shown supporting a panel 21 and a decorative upper bar 22. As will become evident, post P4 is not required, kinematically speaking.

However, it may provide added rigidity to base frame 12 and also provide the bed with typical bed symmetry, or to support panel 21 If desired, bar 16 neec. not extend to the two posts but merely form a handle for convenience.

One of the major features of the uniqueness of the bed relates to the fact that an upper frame 25, on which the mattress on which the patient rests, is controlled by only three drive mechanisms in posts 25 - P3, one in each post. The unique manner in which these three mechanisms operate will be described in detail At this point it should be pointed out that as shown in Fig. 1 the upper frame 25 does not extend all the way to post P4 which is not connected thereto. Thus, a space is created at the right side of the bed near the footboard 20f. At that point the main base frame 12 includes only its low support bar 12a. By properly operating the mattress, as hereafter described, the mattress can be shaped into a chair and the patient can get off the bed by merely stepping over support bar 12a, which is practically at floor level.

It should be pointed out that in a preferred arrangement the frame 25 is lowered to G minimum level and the leg section 8 A is partially tilted as shown in Fig. 1 so that a patient can get off the bed by merely sliding off section 84 by turning his feet to the right.

This is easily accomplished since as shown in Fig 1 the upper frame does not have a ledge which extends all the way to post P4.

The novel manner in which the upper frame 25 is supportable by mechanisms in only three posts may partially be described by one implementation of a drive mechanism in each post.

Part of the mechanism in each of posts P1 - P3 will first be described in connection with Fig 2.

Basically in each post, e.g. P2, a motor e.g. a motor 30 (see Fig. 1) is used to turn a lead screw which is properly mounted in the post by appropriate bearings.

Fig. 2 is a cross-sectional view of post P2. The lead screw isdesignated by 32. A nut 35 with opposite ears 36 travels on the lead screw 32 as the latter rotates. The function of the ears 36 is to define an axis of rotation about which a yoke-shaped member 38 with a yoke shaft 40 are adapted to rotate or pivot under certain circurstances to be described. As shown in Fig 2 the yoke shaft 40 exits the post P2 through an elongated opening 42 to perform functions to be described in connection with Fig. 3 to which reference is made. Fig. 3 is essentially a kinematic diagram of the manner in which the upper frame 25 is connected, supported and operable by the drive mechanisms in the three posts P1 - P3. The inner mechanism associated in each of the three posts is the same.However, externally, each yoke shaft is connected differently to the upper frame at one of its three corners.

As to post 1, the yoke shaft 40 forms part of a revolute joint 42. An outer joint member 44 can only rotate about yoke shaft 40 of PI. Member 4 is rigidly connected to frame 25. It should be apparent that the coupling between frame 25 and the nut in P1 has two degrees of freedom. They are pivotal or rotational motion of shaft 40 about the axis, defined by ears 36, and rotary motion between shaft 40 and member The mechanism in post P2 is very similar except that its yoke shaft 40 forms part of a cylindrical joint 50.

The outer member of joint 50 is designated by 52 and is shown rigidly connected to the frame 25 at 53 b an extension 54. Clearly, in a cylindrical joint both relative linear and rotational motion between shaft 40 and outer member 52 are possible. Thus, the frame-to-P2 coupling arrangfflment has three degrees of freedom.

Finally, as to the coupling arrangeront between P3 and the frame 25: it has four degrees of freedom, the shaft 40 is part of a revolute point 60 with an outer member 62. TUp to this point the arrangement is similar to that for post P1 and the frame. However, in the post P3 linking members 64 and 65 are included. At one of their ends they are pivotably connected te one another by pivot joint 66. while the other ends of members 64 and 65 are pivotably connected to member 62 and to the frame, respectively, at 68 and 69. They are later described in greater detail in connection with Fig. 10.

When the nuts 35 (see Fig. 2) are at the same horizontal level all the yoke shafts 40 are horizontally aligned and so is the frame 25. To cause frame 25 to pitch, i.e. lower or raise its foot end 25f, with respect to the head end 25h the motor associated with P2 is turned, thus turning the lead screw 32 in post P2. If the nut rises the shaft 40 pivots down thus lowering the foot end 25f which corresponds to raising head end 25how In this case the yokes 38 and shafts 40, simply pivot about the nut ears 36. Thus, one can state that the frame can be pitched by activating a motor at its foot end to cause the frame to rotate parallel to its head end or about the width of the frame or mattress. The same can be achieved by activating the motors in posts P1 and P3, simultaneously.

As te causing the frame 25 to roll, the motor associated with the lead screw in post P3 is activated By raising or lowering the nut the shaft 40 is raised or lowered and through joint member 62 and the pivotally linked arms 64 and 65 the frame end to which pivot joint 69 is coupled rises or falls. As a result the entire frame 25 rotates about the axis defined by both shafts 40 of posts 1 and 2. Kinematically, the three mechanisms of the three posts allow the frame 25 to be pitched and rolled at the same time.

It should be clear that by simultaneously turning the lead screws in all three posts, i.e. activating the three motors associated with them, the frame can be raised and lowered.

As shown in Fig. 1, the function of the upper frame 25 is to support a multisection bo spring or the like on which a mattress can be placed for a patient to rest thereon.

For simplicity, instead of referring to the sections of the box spring, reference will be made to the mattress sections, since it is the mattress on which the patient lies.

In Fig. t the entire mattress is designated by 75.

It includes, from top to bottom, a back section 81, a buttocks section 82, a thigh section 83 and S leg section 84. Tpically, though nct necessarily, the section 82 is fixedly attached to frame 25. The frame 25 also supports mechanisms to separately control the angles between fied section 82 and the other sections. The angular orientation of each of the other secticns, i.e.

the back section 81, the thigh section 83 and the leg section 84 can be changed for the patients comfort or healing process.

In most if not all beds, the angular actuation of the thigh and leg sections are interdependent. That is, as the thigh section is raised the leg section automatically tilts downwardly. This is not the case in the present invention. Herein a separate mechanism is supported by and under frame 25 to control the angular orientation of each cf sections 81, 83 and 84 indepently. One example of such a mechanism will be described hereafter. At this point it is sufficient to point out that in one emWcdiment each mechanism includes a motcr which turns an element, e.g. a lead screw on which a nut travels. The nuts or Pins which extend therefrom are used as pivots coupled to linkages, which are in turn attached to the back of the section they are to control. A potentiometer is attached te the lead screw to provide an indication o the sections angular orentation with respect to frame 25.

From the foregoing, it should thus be apparent that to control the three mattress sections 81, 83 and 84, three separate motors are used. By actuating one, two or all three of these motors a practically infinite umber of combinations of sections' positions may be attained.

As to the orientation of frame 25; as herebefore explained, three motors are also required, one in each Gf posts 1 - P3 te control its position in height about a vertical axis (when the frame is in a horizontal plane), in pitch and roll. Thus, with six motors all aspects of the bed can be controlled.

As shown in Fig. 1 the upper frame 25 does not extend along the entire right side of the bed as viewed from the head end at which posts P1 and P3 are located to the foot end, whereat posts P2 and P4 are positioned.

Rather, it only extends partially from the head end up to about section 82 or 83. This is possible due to the fact that post P4 is not used tc support the upper frame 25.

Thus a significant gap is formed in the right side of the upper frame above recess 12a in lower frame 12. This gap or open space is most significant for the following.

There are many patients who, though bed-ridden, are perrritted and wish to get off the bed for a short stroll, use the wash room, etc. This is generally not possible with most hospital beds, even those with adjustable mattress sections. This is due to the fact that the mattress is supported on a continuous rectangular frame, supported et both ends of the bed. Thus, even if the frame is lowered and the mattress back section raised, the leg section is flat This makes it quite difficult for the patient to get off cr on the bed without a nurse's assistance. This imitation which does not sexist in the present invention, may test be explained in connection with Figs. 4a and 4b.

In Fig. 4a, the upper frame 25 is shown in a thigh position and the mattress 75 in a flat or examination position. The wheels 13 are shown supporting the hollow lower base frame 12 slightly above a floor 90. For a patient to get off the bed the mattress sections need be positioned in a chair position as shown in Fig. 4b and the frame 25 lowered toward the floor. This order may be reversed.

That is, the frame 25 may first be lowered and then the mattress converted into the chair position. In this position the back section 81 is nearly perpendicular upwardly, sections 82 and 83 are substantially flat, while the leg section 84 is lowered until its end is very close to the floor.

Once in this position the patient can easily step off the chair-shaped mattress and over the lost section 12a of the base frame 12 and thus get off the bed. It should again be stressed that this important feature is possible because the upper frame does not extend to post P.

Frame 25 extends only partially below the mattress. Thus a space is created above the foot end of the bed above frame 12 into which the leg section 84 can tilt downwardly. As previously pointed out the frame 25 can be lowered and the patient can slide off the bed from a position as shown in Fig. 1.

It should be stressed that the lower frame 12 is rectangular. As a result, even if the patient were to place his (or her) entire weight on section 83 and/or 84 which are off frame 25, the bed does not become unbalanced. In fact the bed is designed to remain balanced or stable on the floor 90 even if a visitor were to sit on any mattress section which is not supported directly by frame 25.

Alternatively stated, the bed 10 comprises a base frame 12 which is supported above the floor at two opposite ends, e.g. the head end 20h and the foot end 20f of the frame, viewed along the length of the bed which are spaced apart a distance greater than the mattress length. The mattress is in turn supported on an upper frame. In any combination of the positions of the mattress sections, the sections are all within the space of the bed defined by the dimensions of the length and width of the lower base frame.

While the mattress positions in Fig. a is the flat or examination position and that in Fig. 4b is in the chair position, the one shown in Fig. 1 is regarded as the couch position, also shown in side view in Fig. 5a- As previously pointed out, unlike most prior art beds, i the novel bed of the present invention the orientations of the thigh and leg sections with respect to the plane of frame 25 are not interdependent. As shown, for example, in Figs.Sa-5c, while the orientation cf thigh section 83 with the frame 25, not shown, but assumed to be horizontal, forms the angle a, the leg section 84 is free to assume different orientations This is due to the facet, previously mentioned, that the orientation of each of sections 81, 83 and 84 is independently controllable.

The mattress orientation shown in Fig. Sc is one in which sections 83 and 84 are in the same plane, forming the same angle a with the frame 25. This position is quite desirable and comfortable for a patient with a leg cast.

Thus, it may be referred to as the cast position.

Unlike the positions described so far, those shown in Figs. 5d and 5e are deemed unacceptable. In the Fig. 5d orientation the angle formed by leg section 84 is 5, where B > > . Such a position would cause an unnatural or reverse force to be applied to the patient's knees and thus is to be prevented Another position which should be prevented is that shown in Fig. 5e, wherein the angle formed by the orientations of the back section 81 and thigh section 83 is e where e < 90". Such a mattress orientation would tend to fold the patient over between its sections.

It should be apparent that both the ori2r.t2tion of frame 25 in height, pitch and roll as well as the orientation of each of the three tiltable mattress sections 81, 83 and 84 may be selected by manually activating appropriate drive means, e.g. motors. As previously pointed out, associated with the lead screw 32 (see Fig. 2) in each of posts P7 - P3 is a motor which turns the lead screw which in turn raises or lowers the nut 35 with its protruding ears or pins 36, about which the yoke 38 with shaft 40 pivot. A potentiometer is coupled to the lead screw to provide an output voltage which is indicative of nut height.The motors associated with posts P7 - P3 may be designated as M1 - M3, respectively, while the voltages from the potentiometers associated with these posts may be referred to as V1 - V3, respectively.

For manual operation of the frame 25, orientation the main aspect which may present a problem is to vary the frame height. To this end all three nuts have to be substantially at the same height and vary synchronously, i.e. at the same rate. It can of course be doe b simultaneously actuating all three motors NI - 3 and observing that none of VN - V3 varies from the others by more than a given tolerance value, designated K. Preferably however this can be accomplished by either a special purpose small computer or properly programmed microprocessor. Such a microprocessor can also perform other functions as will be described.

As to controlling the orientation of each of mattress sections 81, 83 and 84, it should be apparent to those familiar with the art that different electromechanical arrangements may be employed. In response to either a manually supplied signal or a computer supplied signal, a motor is actuated to move appropriate linking arms to raise or lower the mattresssection with which the electromechanical arrangement is employed In one particular embodiment a motor, lead screw, nut, and potentio=er combination, defining an actuator is used as part of each electromechanical arrangement As shown in Fig. 6 which is a simplified crosssectional and block diagram of a typical actuator 100, enclosed within its housing 102 is a lead screw 104.It is supported by bearings 105 and 106. The lead screw is driven by a motor 108 through a gear box 109. A nut 110 is threaded on the lead screw 104 with a pin 115 extending from it perpendicular to the longitudinal axis of lead screw 104, A potentiometer 117 provides an output voltage.

A pierced protrusion or ear 120 extends from one end of the actuator housing 102 and is adapted two receive a pivot pin in its hole 121 The manner in which such an actuator 100 is used in the electromechanical arrangement for controlling each of the mattress 2ctions 81, 83 and 84 may best be explained in connection with Figs. 7, 8 and 9. In Fig. 7 is an arrangement useful in explaining the manner of raising and lowering the thigh section 83. In this arrangement a pin 125 fixedly positioned to frame 25 is in hole 121 of ear 120. Thus, the actuator can pivot about it.

Pin 115 extends out of a slot 125 in actuator housing 102 and serves as the pivot point at the apex of a pair of V-joined arms 126 and 127, whose other ends are mechanically and fixedly coupled to the back side of thigh section 83.

To raise this section the motor in the actuator is rotated to rotate the lead screw to move pin 115 to the left. The actuator body 102 may rise slightly due to the pivoting action about pin 125. However, by the pin 115 moving to the left the arms 126 and 127 rise, thus raising or more precisely tilting thigh section 83 upwardly as the point between it and section 82, designated 135, is fixed to the frame. The output of the potentiometer of actuator 100 is calibrated to provide a voltage indicative of the thigh section angle designated aT in Fig. 7.

A similar, though slightly different arrangement, is employed to control the orientation of back section 81 as shown in Fig. 8. In this arrangement the pin 115 is pixedly connected to the frame. Thus the actuator body 102 can only move and pivot about pin 115 A triangularlyshaped link 140 and a bar-shapeå link 144 are provided.

Link 140 is pivotably connected to a fixed pivot 150, to ear 120 at point C and to link 144 at point B. The other end of link 144 is pivotably connected to the back section 81 at point A In Fig. 8 the solid lines show the various elements when the back section 81 is flat, and in dashed lines when it is practically vertical For the sake of completeness, rather than to limit the invention thereto, attention is directed to Fig. 9 where an arrangement for controlling the leg section 84 is shown. The arm 120 of actuator ;00 is pivotally connected to the frame. Pin 115 extending out of slot 125 of actuator 100 acts as the pivot at one end of a linking bar 160, the other end of which pivots about the junction between sections 82 and 83 at 161.The pin 115 also serves as the pivot for a linking bar 162, the other end of which is also pivotably coupled at 164 to the apex of two bars 165 and 156. The latter are rigidly connected to the back of leg section 84.

Points 161, 115, 167 and 168 (axis between 83 and 84) define a parallelogram which is needed in order to control the tilt of section 84 independently of section 83.

If the angle of section 83 is changed while the actuation of Fig. 9 is not actuated, section 84 will translate only keeping its tilt constant.

The arrangement is shown when the leg secticr.

84 is in the flat or horizontal position. To lower section 84 as the motor turns the lead screw lr.

actuator 100, the nut and pin 115 travel up the slot 125 pulling with it bar 162 which in turn pulls arms 165 and 166, The potientiometer output of actuator 100 is indicative of the angle of the leg section 84.

In Fig. 2 it was assumed that the yoke shalt 'O was a straight rod extending from yoke 38 out of the post opening 42. Such an arrangement was presented for explanatory purposes only. In fact, the yoke 38 extends slightly out of the opening 42 and then terminates in a mounting surface to which the shaft 40 is connected. Such an arrangement is show in Fig. 10 for the extericr part of the coupling mechanism between post P3 and the frame 25. Therein elements like those shown in Fig. 3 are designated by like numerals.

Basically, yoke 38 from post P3 terminates in a plate 40a which is securable to a like plate 40b by bolts and nuts (not shown Extending from plate 40b is a shaft portion 40x, which together with outer member 62 form; the revolute joint 60. The other elements shown in Fig. 10 corre-spond to those in Fig. 3 for the coupling arrangement of post P3.

As should now be apparent from the foregoing, in the novel bed of the present invention, a lower base frame 12 provides the basic support for the bed 10 and defines its rectangular boundaries. It supports three posts P1 - P3 as well as a fourth post Pg, which effectively can be ignored other than for decorative purposes and give the bed typical symmetry. An upper frame 25 is coup led through three coupling mechanisms which are partially within posts P1 - P3 and partially outside.

It is these coupling mechanisms which are used to control the orientation of the frame 25 in roll and pitch about two orthogonal axes, as well as the translational motion (height along the third (vertical) axis.

The frame can be raised or lowered, when being in a horizontal plane or in any other orientation, about a vertical axis It can be made to pitch about an axis parallel to its width, such as by actuating motor M2 in post P2. It can also be made to roll about its longitudinal axis by the actuation of the motor M3 in post P3. All of these orientations are imparted to the mattress which is supported on the upper frame 25.

As described1 at least three of the mattress sections are tiltable, each by its own electromechanical mechanism. It includes a motor which is used to produce the desired angular tilt of the mattress section and a potentiometer whose voltage output is indicative of the section's angular orientation. Thus, three motors and three potentiometers are needed to control the orientation of frame 25 and a like number of motors and potentiometers for the mattress sections. Therefore, by controlling up to six motors and monitoring six voltages from te six potientiometers, all possible frame and mattress combinations may be controlled.For explanatory purposes the motors and voltages from the potentiometers associated it back section 81, thigh section 83 and leg section 88 will be designated hereafter by M3, V3, MT, VT and ML and VL, respectively.

As previously pointed out, most if not all possible functions may be performed by manual actuation of the motors by a patient or a nurse. However, to optimize the bed's performance as well as automatically prevent unacceptable situations, some of which were described in connection with Figs 5d and 5e from arising, it is preferable to computerize the bed. As used herein, computerization intends to mean using any known devices to respond to manual control signals to drive one or more of motors M1, M2, M3, MB, MT and E , while monitoring V1, V2, V3, VB, VT anà VL, i.e. the output voltages of the six potentiometers.By so operating, the requested performance, based on the manual control signal, is performed yet inhibiting unacceptable conditions from occurring.

Generally, such an arrangement may be described in connection with Fig. 11. Therein block 180 designates a signal processor, such as a microprocessor or the like.

Attached to the bed 10 is a control unit 185. It is used by the patient, nurse or doctor to actuate switches, buttons or the like to send specific control signals to the processor 180. Based on these signals and the voltages from the six potentiometers, the processor 1C0 activates one or more of the six motors as required to affect the operation, while continuously monitoring the voltages to prevent undesired conditions from occurring.

Based on the present state of the art of programming a microprocessor or the like, it should be apparent that different sequential operations may be prog-a.med in order to perform desired functions as well as undesired ones. For example, one set of instructions may be written to lower or raise frame 25 when it is substantially flat. On the other hand, a different set of instructions may be written to lower or raIse the frame 25 when it is in roll and/or pitch. Also the pitch or roll limits may be varied. Furthermore, unacceptable conditions may be defined other than those previously discussed. Also, if desired one or more certain conditions of the bed may be stored in memory so that by the press of a button the bed may be returned automatically to one of these conditions. Since the art of programming is well shown and the variables in the novel bed have been described, it is believed that providing specific examples of flow charts will not add information to those familiar with the art.

Although particular embodiments of the invention have been described and illustrated herein, it is recognize that modifications and variations may readily occur to those skilled in the art and consequently, it is intended that the claims be interpreted to cover such modifications and equivalents.

Claims (14)

1. A bed comprising: a substantially rectangularly shaped base frame defining the length and width of said bed; an upper frame; first control means including three control units for selectively controlling the position of said upper frame, said three control units being partially disposed at substantially three corners of said base frame and extending vertically therefrom, with said upper frame being selectively controllable in height above said base frame and in roll and pitch about axes substantially parallel to the bed length and width.

2. A bed as recited in Claim 1 wherein each control element includes a pivot controllable in height and means pivotable about said pivot and connectable to the upper frame to control the orientation thereof.

3. A bed as recited in Claim 2 wherein said bed includes at least three posts with a portion of each control element partially housed in one of said posts.

4. A bed as recited in Claim 3 wherein each control unit in a post includes a motor driven lead screw, with the height of said pivot being a function of the rotation of the lead screw.

5. A bed as recited in Claim 1 further -r.cluQins a multisection mattress on said upper frame, including a back section, a thigh section and a leg section, and means for independently controlling the orientation of each of said sections with respect to said upper frame

6. A bed as recited in Claim 5 wherein said upper frame is shaped whereby said leg section is tiltable below the upper frame, within the boundaries of said base frame.

7. A bed as recited in Claim 6 wherein each control element includes a pivot controllable in height and means pivotable about said pivot and connectable to the upper frame to control the orientation thereof

8. A bed as recited in Claim 7 wherein said bed includes at least three posts with a portion cf each control element partially housed in one of said posts

9. A bed as recited in Claim 8 wherein each control unit in a post includes a motor driven lead screw, with the height of said pivot being a function of the rotation of the lead screw.

10. An arrangement comprising: a rigid frame; and control means for controlling the orientation of said frame about three orthogonal axes, said control means includinc first, second and third elongated control units, and coupling means for coupling each of the units to said frame. the units being oriented parallel to one another with their longitudinal axes perpendicular to a horizontal plane, each unit including an element being moveable along the longitudinal a:is of the unit, and linking means for linking the moveable element of each unit to said frame, to control the orientation of the frame.

11. An arrangement as recited in Claim 10 wherein said moveable element comprises a pivot extending perpendicular to the unit's longitudinal axis, and said means for linking include means for pivoting about said pivot.

12. An arrangement as recited in Claim 10 wherein said frame is orientatable in height pitch and roll.

13. An arrangement as recited in Claim 10 wherein said first, second and third control units are characterised by two, three and four degrees of motion, respectively.

14. An arrangement as recited in Claim 10 wherein each control unit includes a rotatable lead screw.