Adjustable BedFree Patent Search

Adjustable bed table

Adjustable Bed Abstract:
A bed table with a vehicular mounting provides adjustable support for a person in a number of different postures, including a reclined table-like configuration and an erect chair-like configuration. The bed table is segmented into three portions, a head support portion, a medial or central support portion, and a leg support portion. The head support portion and leg support portion are pivotally mounted to a support base and are interconnected with linkage such that the leg support portion follows the rotational displacement of the head support portion. A pneumatic or hydraulic actuator is attached to the head support portion and is controlled through a control panel for automatic operation of the bed table, between the reclined table-like and erect chair-like configurations. An energy source for the actuator is provided by a vessel containing compressed nitrogen. The bed table is provided with a bedpan, swingably mounted into and out of engagement with the central support portion. When mounted against the central support portion, the bedpan is aligned with an aperture extending to the upper surface of the bed table.

Adjustable Bed Claims:
What is claimed is:

1. A vehicular mounted bed table apparatus for adjustably supporting a person in a number of different postures, comprising:

a segmented table top having a head support portion for supporting the person's head, a double ended medial support portion for supporting the person's mid-section, and a leg support portion for supporting the person's legs;

a vehicular frame for supporting the table top;

means for mounting at least said medial support portion to said vehicular frame;

means for pivotably connecting said head support portion to one end of said medial support portion;

means for pivotably connecting the leg support portion to the other end of said medial portion;

pressure-responsive fluidically operated displacement means connected to said head support portion for pivotable displacement of said head portion with respect to said medial support portion to thereby raise and lower the upper portion of a person reclining on said bed table;

pressure means for imparting fluidic pressure to said fluidically operated displacement means, and a bedpan mounted to said medial support portion, including means for raising and lowering said bedpan with respect to said medial support portion, wherein said means for raising and lowering said bedpan comprises means mounted to said medial support portion for pivotably swinging said bedpan into and out of engagement with said medial support portion.

2. The apparatus of claim 1 further comprising means connecting said head and leg support portions so as to pivotably displace said leg support portion with respect to said medial support portion in response to the pivotable displacement of said head support portion.

3. The apparatus of claim 2 wherein said connecting means comprises a double-ended linkage means pivotably connected at first and second ends to said head and said leg support portions, respectively.

4. The apparatus of claim 1 wherein said fluidically operated displacement means comprises a cylinder having a mounting end and a piston rod extendable and retractable out of and into said cylinder, said mounting end mounted to said vehicular frame, and means for pivotably mounting said piston rod to said head support portion, said cylinder responsive to said pressure means to extend and retract said piston rod so as to raise and lower said head portion, respectively.

5. The apparatus of claim 4 further comprising linkage means interconnecting said head and said leg support portions so that said leg support portion is lowered as said head portion is raised, and so that said leg support portion is raised as said head portion is lowered.

6. The apparatus of claim 1 wherein said pivotable mounting means comprises at least one pivotally interconnected pair of parallel linkage members on either side of said bedpan.

7. The apparatus of claim 6 wherein said pivotable mounting means includes a support tray with at least three spaced-apart points spaced about said mounting means, each support point pivotably swung by said linkage members.

8. The apparatus of claim 6 wherein said pivotally interconnected pair of parallel linkage members comprises a first generally horizontal linkage member adjacent the bedpan and a second, generally horizontal linkage member adjacent the bed table, first and second interconnecting hanger members pivotally connected at first ends to one linkage member and pivotally connected at the other ends to the other linkage member through relatively short connector links.

9. The apparatus of claim 8 further comprising a double-ended crank handle pivotally mounted to the vehicular frame at a medial portion, and having a pivotal connection at one end, and further comprising a third linkage member pivotally connected at one end to the crank handle and pivotally connected at the other end to one said connector link.

10. The apparatus of claim 1 further comprising arm support means mounted to at least one of said medial support portion and said vehicular frame; and

means for mounting said arm support for movement between raised and lowered positions.

11. The apparatus of claim 1 further comprising a locking flange depending from said arm support and movable therewith between raised and lowered positions, the locking flange being engageable with a patient's bed frame so as to lock the bed table apparatus to the bed frame to prevent relative movement therebetween as the patient is transferred therebetween.

12. The apparatus of claim 1 further comprising a generally L-shaped overhead support having a first leg with a free end mounted to the vehicular frame and a second leg extending over the bed table with a free end positioned adjacent one side of the bed table.

13. The apparatus of claim 1 further comprising an adjustably movable footrest located at a free end of the leg support portion, the footrest being removably engageable with the lateral sides of the leg support portion so as to be selectively positionable toward and away from the medial support to accommodate patients of different body height.

14. The apparatus of claim 13 further comprising toothed racks at each lateral side of the leg support portion, the foot support further comprising arms having free ends, and pawls located at the free ends engageable with teeth of the racks for securement therebetween, when pivoted theretoward.

15. The apparatus of claim 14 wherein said means for raising and lowering said bedpan comprises a bedpan-supporting table having rectangular configuration with four corners, hanger arms having lower ends pinned to each corner of the support table, an elongated shaft extending between one pair of hanger arms and fixably attached thereto, a first stub shaft rotatably attached to the third hanger arm, a second stub shaft having first and second ends with the first end fixedly pinned to the remaining hanger arm, a first connector link having a second end and a first end fixedly attached to the second end of said second stub shaft, a second connector link having a first end fixedly attached to said elongated shaft and a second end, and an intermediate link having two ends pivotally connected to the second ends of said first and said second connector links, so that a force applied to the intermediate linkage arm is transmitted to three of the four corners of said table through said hanger arms and is further transmitted to the remaining corner of said support table through two separate portions of said support table.

16. The apparatus of claim 15 further comprising a crank arm having one end pivotally connected to the pivotal connection of said intermediate link arm and said one connector link, and a pivotally mounted crank handle having a first manually graspable end and a second end pivotally connected to a second end of said crank arm.

17. A vehicular mounted bed table apparatus having bedpan facilities, comprising:

a segmented table top for adjustably supporting a person in a number of different postures, including a head support portion for supporting the person's head, a double-ended medial support portion for supporting the person's midsection, and a leg support portion for supporting the person's legs;

a bedpan mounted to said medial support portion;

means for raising and lowering said bedpan including means mounted to said medial support portion for pivotally swinging, said bedpan into and out of engagement with said medial support portion;

a vehicular frame for supporting the table top and the bedpan;

means for mounting at least said medial portion to said vehicular frame;

means for pivotally connecting said head support portion to one end of said medial support portion;

means for pivotably connecting the leg support portion to the other end of said medial support portion;

pressure-responsive fluidically operated displacement means connected to said head support portion for pivotably displacing said head support portion with respect to said medial support portion so as to raise and lower the upper portion of a person reclining on said table top; and

pressure means for imparting fluidic pressure to said fluidically operated displacement means.

18. A vehicular-mounted bed table having a bedpan apparatus swingably mounted thereto for installation and removal therefrom, comprising:

a segmented table top having a head support portion for supporting a person's head, a double-ended medial support portion for supporting the person's midsection, and a leg support portion for supporting the person's legs;

a bedpan swingably mounted to said medial support portion;

means for raising and lowering said bedpan comprising pivotable mounting means secured to said medial support section pivotally interconnected to at least three spaced-apart support points spaced about the outer periphery of the bedpan;

a vehicular frame for supporting the table top;

means for mounting at least said medial support portion to said vehicular frame;

means for pivotably connecting said head support portion to one end of said medial support portion;

means for pivotably connecting a leg support portion to the other end of said medial support portion; and

pressure-responsive fluidically operated displacement means connected to said head support portion for pivotable displacement of said head support portion with respect to said medial support portion to raise and lower the upper portion of a person reclining on said table top.

Adjustable Bed Description:
BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention pertains to a bed table comprised of movably interconnected sections which can be reconfigured as a chair. More particularly, the present invention pertains such tables having bedpan facilities.

2. Description of the Prior Art

Mobile bedside tables have been provided with a height suitable for coplanar alignment with a patient's bed so as to facilitate the patient's ability to slide onto the table. When provided with vehicular mounting, such tables can be used by an attendant to easily transport a patient from one location.

For patients who are unable to use remotely-located bathroom facilities, bed tables have been provided with commode or bedpan facilities. The tables may have one or more foldable sections to approximate roughly the configuration of a chaise lounge. Examples of these types of bed tables are given in U.S. Pat Nos. 1,560,422; 2,500,544; and 2,899,694. U.S. Pat. No. 3,050,741, for example, has multiple sections, foldable into a chair-like configuration.

Each of the above U.S. patents has vehicular mounting to provide patient transport from one location to another. When located in a hospital, for example, the vehicular mounting allows the bed table to be moved between patients' rooms, upon demand. This offers an improvement over the stationary convertible bed of U.S. Pat. No. 4,282,613, for example. Also, the bed tables with vehicular mounting need not be integrated into a particular bed structure, as in U.S. Pat. Nos. 2,500,741; 2,500,743; 3,503,083; 4,190,913; and 4,085,472, all of which are built into a patient's bed structure for dedicated use therewith.

It is important, especially when a bed table vehicle with bedpan facilities is shared among different patients, that the bedpan be quickly and easily removed for service at a remote location. Accordingly, there is a need for a simple and efficient system for moving the bedpan into and out of position. U.S. Pat. No. 2,204,343, for example, discloses a relatively massive mechanism operated by a hand crank, for raising and lowering a bedpan into and out of position.

Although the above bed tables with bedpan facilities have been provided in a variety of different styles and arrangements, improvements are still being sought and there is a strong demand for bed tables having most or all of the following features. For example, many of the convertible bed tables have hand cranks for raising a back support portion of the table or for reconfiguring the table into a chair. While it may be a relatively simple matter to operate the crank on an empty bed table, considerable physical effort is required when a bed table is converted into a different configuration with a patient lying on the table. This is, however, one o the attractive features of a bed table convertible into a chair or the like.

While this problem is alleviated by employing electric motors as the energy source for raising and lowering a patient on a convertible bed table, motorized arrangements suffer from a number of deficiencies. First, the bed table must be located at or near a supply of electrical current which might not be readily available at all locations of use. For example, when a bed table is employed in a domestic setting where the patient's sickroom may not have a electrical outlet immediately adjacent the desired location for the patient's bed. Further difficulties are encountered with beds having electric motors which are employed to raise and lower a patient. Depending on their physical condition, some patients find maintaining an erect body posture very exhausting even for relatively short periods of time. If a power failure should occur while the table is in an upright position, the patient may be made to experience a considerable amount of discomfort, particularly when being transported back into a bed. Further, even if hand cranks are available in such emergency conditions, an operator of the bed table, particularly in a domestic setting, might not be familiar with the crank and locking systems for the particular bed, and may not be familiar with mechanisms of that type in general. For larger patients, a considerable amount of force is applied to the mechanism particularly as the back support portion of the table is inclined at successively lower positions. As has been observed, older and informed patients might become alarmed at even the slightest sense of an uncontrolled condition in the apparatus supporting their body. It is, therefore, desirable that a bed table, particularly one with a vehicular mounting be completely self contained with its own separate uninterruptable energy source.

Frequently, a patient will be treated with oxygen, or other inflammable materials might be located proximate the patient's bed. The bed table should be safe for use in these and other hazardous environments.

It is desirable that bed tables having bedpan facilities, and particularly such bed tables shared with a number of different patients, be suitable for frequent steam cleaning and not have components such as greased mechanisms or electrical motors which are susceptible to damage when steam cleaned.

In providing convertible bed tables suitable for use with bedpan facilities, it is generally desirable that a patient be provided with an erect sitting posture. Accordingly, it is important that the bed table have foot and leg support as well as back support sections which are movable to approximate a chair-like position as closely as possible. It is also desirable that a bed table of this type be configurable to intermediate positions for patients who, for one reason or another, cannot be moved to completely erect positions.

It has been found that patients who can move themselves onto a bed table prefer to do so, even if such requires a great effort, rather than requiring an attendant's help. Such patients, it has been found, also prefer a bed table which will automatically change configurations into a chair-like position. It is desirable to provide these patients with an automatic system subject to their own control, for configuring the apparatus between chair-like and table-like configurations.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide an automatically operated bed table, having a self-contained energy source.

Another object of the present invention is to provide a self-contained bed table which does not require connection to external supply lines, such as an electrical outlet.

A further object of the present invention is to provide a bed table which is automatically convertible from a table configuration, and which can optionally be operated by a patient supported by the bed table.

Yet another object of the present invention is to provide a bed table having automatic operation, which is safe for use in an oxygen atmosphere or other hazardous environment.

Still another object of the present invention is to provide a bed table of the above-described type which is not deteriorated or otherwise impaired by steam cleaning or the like.

Another object of the present invention is to provide a bed table having fail-safe operation, with stored energy means for the controlled conversion of the apparatus to a bed table configuration.

A further object of the present invention is to provide a bedpan for use with a bed table having a mounting for swinging the bedpan into view during loading and unloading from the bed table.

A further object of the present invention is to provide a three-section bed table having head, intermediate and foot portions, in which the head and the foot portions move together in a predetermined relationship.

These and other objects of the present invention are provided in a vehicular mounted bed table apparatus for adjustably supporting a person in a number of different postures. The bed table has a segmented table top including a head support portion, a double-ended medial support portion for supporting a person's mid-section, and a leg support portion. The table top is supported by a vehicular frame, and means are provided for mounting at least the medial support to the frame. The head support portion can be pivotably connected to one end of the medial support, and the leg support portion can be pivotably connected to the other end of the medial portion. Pressure-responsive, fluidically operated displacement means are connected to the head support portion for pivotable displacement of that portion with respect to the medial support portion, to allow raising and lowering of the upper portion of a person reclining on the bed table. Pressure means are provided for imparting fluidic pressure to the fluidically operated displacement means.

Other objects of the present invention are provided in a bed table of the above-described type having a bed pan swingably mounted to tee medial port portion thereof. The swingable mounting for the bedpan can be provided by pivotally interconnecting linkage supporting the bedpan at three or more spaced-apart points along its outer periphery, swingably displacing the multiple peripheral points of the bedpan simultaneously.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, wherein like elements are referenced alike,

FIG. 1 is a perspective view of an adjustable bed table illustrating features of the present invention, shown in a first flat, table-like configuration;

FIG. 2 is a perspective view of the adjustable bed table of FIG. 1 shown reconfigured to a chair-like position;

FIG. 3 a side elevational view of the adjustable bed table of the preceding FIGURES;

FIG 4 is a side elevational view of the adjustable bed table configured to assume a chair-like position;

FIG. 5 is a fragmentary elevational view showing the control panel portion of the adjustable bed table in greater detail;

FIG. 6 is a fragmentary elevational view showing the adjustable bed table clamped to a side of a patient's bed;

FIG. 7 is a fragmentary perspective view of the of the adjustable bed table;

FIGS. 8 and 9 are fragmentary side elevational view of the framework portion of FIG. 7 shown in table-like and chair-like configurations, respectively;

FIG. 10 is a perspective view of an apparatus for mounting the bedpan to an adjustable bed table;

FIG. 11 is a side elevational view of the bedpan mounting apparatus of FIG. 10;

FIG. 12 is a side elevational view similar to that of FIG. 11, but showing the bedpan in a raised, operative position;

FIG. 13 is a fragmentary side elevational view of the adjustable bed table of FIG. 3 showing the foot support portion in greater detail;

FIG. 14 shows the foot support being moved from one position to another;

FIG. 15 is a fragmentary elevational view of the foot support portion of FIG. 13 taken along the line 15--15 thereof; and

FIG. 16 shows the fluidically-operated pressure cylinder of the preceding figures, in greater detail.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawings, and especially to FIGS. 1-4, an adjustable bed table according to features of the present invention is illustrated generally at 10. The bed table 10 includes an upper table top or support surface 12 for supporting a patient in a prone or prostrate position. According to one aspect of the present invention the support surface 12 is segmented into three tabletop sections or support portions including a head support portion 14, a central or medial support portion 16, and a leg support portion 18. The three support portions 14-18, as will be seen in greater detail, are pivotally interconnected so as to be movable between a first table-like configuration as illustrated in FIG. 1 and a second chair-like configuration as illustrated in FIG. 2. In the preferred embodiment the three support portions each include a lower rigid support base covered with a suitable chemical resistant fabric such as a Teflon or a Teflon coated glass fabric. The three support portions are preferably padded with a material suitable to withstand the rigors of repetitive steam cleaning and the like. An example of the preferred construction will be described herein with reference to FIG. 15. According to one aspect of the present invention, the entire adjustable bed table, including the moving parts and particularly the automatic fluidically operated power system are all suitable for frequent steam cleaning.

The three support portions, 14-18 are mounted on a vehicular-support base generally indicated as 22. Base 22 of the preferred embodiment is formed of an open framework 24 of tubular stainless steel, and includes wall panels 26, 28 as well as other components which will be described herein. The framework of the bed table is preferably formed of tubular stainless steel which is welded at its various joints. Other suitable materials may also be used. However, it is preferred that all materials utilized in the bed table, including the framework members, be chemically resistant and be suitable for repetitive steam cleaning and other cleaning procedures necessary to maintain the bed table and its components in a hygienic condition.

Caster rollers 30 provide a vehicular mounting for the bed table allowing a patient to be carried thereon for convenient transport from one location to another. A floor lock 32 is one of the means provided herein for securing the table against movement, especially when the patient is being transferred between the bed table and a conventional bed. Preferably, the floor lock consists of a housing 34 in which is mounted a movable foot 36 which is both flexible and floating so as to compensate for irregular floors. The foot is spring loaded and is selectively engageable and releasable by operating a foot pedal 38.

FIGS. 3 and 4 illustrate the bed table from a frontal position while FIG. 1 illustrates the bed table from a rearward position. The base 22 is configured to have a suitable height such that the upper surfaces of the support portions 14-18 are generally at the same level as the upper surface of the patient's bed, thereby forming a coplanar extension thereof. After rolling the bed table 10 into a patient's room, the bed table is positioned such that one side (herein the rear side) of the bed table is positioned abutting the patient's bedside, as illustrated in FIG. 6. The bed table illustrated in FIG. 1 is configured for access to the right hand side of the patient's bed with the panel 26, for example, being located adjacent the patient's bedside and with the head portion 14 located adjacent the patient's head and the leg portion 18 adjacent the patient's legs. As will be appreciated, the bed table is conveniently convertible to access the other, left hand side of the patient's bed if desired.

Referring briefly to FIG. 7, the support portions 14-18 have been removed to clearly illustrate the framework 24. The panels, 26 and 28, have also been removed to aid in the clarity of the illustration. FIG. 7 is oriented such that the frontal side portion of the bed table is in the foreground while the rear side portion of the bed table is shown in the background of the figure. Thus, when installed, the panel 26 (visible in FIG. 1) would be at the rear of the table, appearing in the background portion of FIG. 7.

With additional reference to FIGS. 3 and 4, the base 22 includes vertical support members 38, 40, and 42 at the front side of the bed table adjacent the had, central, and leg supporting sections thereof, respectively. Vertical supports 44, 46, and 48 oppose the vertical supports 38, 40, and 42, respectively, being located at the rearward portion of the bed table, that side in contact with the patient's bed. Upper and lower frontal side support members 50, 52 extend the length of vehicular base 22 and are located at the forward end thereof. Similarly, rearward side support members 54, 56 are located at the rearward end of the bed table. Upper and lower transverse support members 58, 60 span the front and back sides of the support base and are located adjacent the head support portion of the table. Similar transverse support members 62, 64 are located adjacent the foot support portion of the table. As thus far described, an open, tubular framework has been provided defining a three-dimensional structure having rectangular sides. Vehicular mounting is provided by caster rollers 30 which are attached to the lower support members 52, 56 at the lower corners of the rectangular framework.

Referring to FIGS. 7 and 10, a rectangular frame generally indicated as 70 is located at the central portion of the bed table and forms an immovable part thereof. Frame 70 includes front and rear side frame members 72, 74 joined at first ends by a transverse frame member 76 located adjacent the head portion of the table and the aforementioned transverse member 62 joining the opposite ends of members 72, 74, adjacent the leg support portion of the table. The members 72, 74 of rectangular frame 70 are welded to the upper side support members 50, 54.

Referring again to FIGS. 7 and 10, upwardly extending hinge plates 80, 82 are secured to the upper support members 50, 54 adjacent the transverse member 76. A rectangular frame-like carrier generally indicated as 84 rests on top of the upper support members 50, 54 having a first free end adjacent the head support portion o the table and a second pivotally mounted end adjacent the central frame 70. The carrier 84 includes side support members 86, 88, an upper transverse member 90 (See FIG. 2) and a lower transverse support member 92. Carrier 84 is pivotally mounted at its lower end by pivot pins 94, 96 attached to hinge plates 80, 82, respectively. Referring briefly to FIG. 9, the head support portion 14 in addition to the frame-like carrier 84 includes a panel 100 of the type described above comprising a rigid backing plate padded with a suitable padding material and covered with a chemical resistant fabric such as teflon. The padded (panel 100 is attached to frame 84 in any suitable manner, but is preferably press fit within the pivotally mounted frame, in the manner illustrated in FIG. 156 A similar construction is illustrated in the cross-sectional view of FIG. 15. Preferably, all three support portions 14-18 have this same construction.

The central support portion 16 of the bed table includes the rectangular framework 70 described above and a padded panel 102 of construction similar to that of the padded panel 100. Panel 102 is preferably press fit within the frame 70.

The third, leg support section 18 of the bed table includes a pivotally mounted rectangular framework 106 including side members 108, 110, an upper transverse support member 112 and a lower transverse member 114 (See FIG. 1). A pair of hinge plates 118, 120 extend horizontally from the side support members 72, 74 of the central frame 70. The framework 106 is pivotally mounted at one end to hinge plates 118, 12 by a pair of coaxially aligned hinge pins 122, 124. The leg support section 18 is completed with the insertion of a padded panel 128 therewithin. As mentioned above, the panels 100, 102 and 128 are similarly constructed. Referring to FIG. 15, panel 128 has a rigid plate-like core 129, which is padded at 130 with a suitable padding and outer fabric covering. Panel 128 has peripheral edges 131 suitable for press-fit retention in the surrounding rigid framework.

Referring now to FIGS. 7-9, the head and leg support portions 14, 18 are interconnected by linkage generally indicated as 134. Hinge plates 136, 138 are welded to the bottom portion of the frame-like carrier 84, adjacent the transverse member 22 thereof. Hinge plates 142, 144 are welded to the framework 106 of the leg support portion 18. A rear link arm 146 pivotally interconnects the hinge plates 136, 142 at the frontal side of the bed table. Similarly, a rear link arm 148 pivotally interconnects hinge plates 138, 144 being pinned at each end to a respective hinge plate. With reference to FIG. 9, as the head support portion 14 is elevated in the direction of arrow 150, the hinge plates 136 and 138 ar rotated about the axis of pivot pins 94, 96. Preferably, the pivot pins 94, 96 are coaxially aligned with one another. This displacement of the hinge plates causes the link arms 146, 148 to be translated in the direction of arrow 152 (See FIG. 9). This in turn causes a pivotal displacement of the hinge plates 142, 144 causing the foot support portion to pivot about its hinge pins 122, 124 in the direction of arrow 154. Thus, by comparing FIGS. 8 and 9, it can be seen that, as the head support portion 14 is elevated, the leg support portion 18 is lowered, thereby reconfiguring the bed table from the table-like configuration in FIG. 1 to the chair-like configuration of FIG. 2.

With reference to the weight distribution along the three portions 14-18 of the bed table, the leg support portion 18 bears the least amount f the patient's weight. According to one aspect of the present invention, lifting support is applied to the head support portion 14 with a pivotally interconnecting linkage 134 causing the leg support portion 18 to follow the motion of the head support portion 14.

In a reclined table-like configuration, the three support portions 14-18 are aligned coplanar, with the frame-like carrier 84 of the head support portion 14 contacting the one support of the upper side support members 50, 54 of the support base. As mentioned above, the central frame 70 is immovably mounted by welding to the support base 22 and has its upper and lower ends proximally located to pairs of upright supports 40, 46 and 42, 48, respectively.

The leg support portion, that loaded the least amount, is supported adjacent its pivotally connected end through the interconnecting linkage 134. The weight borne by the leg support framework 106 applies a compressive loading to the link arms 146, 148 in the general direction of arrow 152 (See FIG. 9). This amount of support for the leg portion 18 has been found to be thoroughly satisfactory. If desired however, one or two struts can be located adjacent the free arms of the leg support portion 18 and the lower portion of the framework 24 preferably adjacent the lower transverse support member 64.

Such optional struts are generally not preferred as a completely automatic operation of the preferred table may be hindered. One feature of the preferred embodiment of the present invention is that the bed table is automatically operable between its table-like and chair-like configurations and, according to one aspect of the present invention, the controls may be provided within reach of a patient supported by the bed table who can, without requiring the presence of an attendant, operate the bed table between its two configurations.

Referring to FIG. 7, the frame-like carrier 84 includes an intermediate transverse member 160 welded at each end to the side support members 86, 88 of the carrier. A bracket 162 is welded to a medial portion of the transverse member, preferably at the center thereof, to provide a pivotal connection for a fluidically operated actuator system which, under the control of the patient or an attendant, configures the bed table between its table-like and chair-like configurations without requiring physical exertion of the person operating the actuator controls. Referring now to FIGS. 2-5 and 16, the actuator system is generally indicated as 166 and includes a pressure-operated cylinder 168 of either the hydraulic (liquid pressure fluid) or pneumatic (gaseous pressure fluid) type. The cylinder includes an outer housing 170 having a pivotal connection at its lower end to a bracket 172. Cylinder 168 includes an internal piston 174 connected to a piston rod 176. The piston rod in turn is pivotally connected to bracket 162. The pressure cylinder 168 preferably comprises a double-action cylinder, with ports 173, 75 (see FIG. 16) at each end. The cylinder may be operated in either a single-action or a double-action mode, and the pressure fluid for its operation may be either a liquid or a gas. If operated in a single-action mode, an internal spring 171 is provided, for reasons to be detailed herein. The port 173 at the bottom of the cylinder provides pressure injection and release during raising and lowering. If operated as a double-acting cylinder, an upper port 175 provides an additional site of pressure injection, for retracting the bed table to a reclined, table-like configuration.

With the bed table in the reclined position, piston rod 176 is withdrawn into housing 170 to assume a first, retracted position. Upon demand, the cylinder 168 is pressurized so as to displace its internal piston 174, thereby extending the piston rod 176. The pivotal connection of the lower end of cylinder 168 to bracket 172 remains stationary while allowing the hydraulic cylinder to pivot about its lower end, between the retracted and extended positions shown in FIGS. 3 and 4, respectively. Upon command, the pressure-operated cylinder 168 can be programmed to automatically retract from the extended position of FIG. 4 so as to draw the piston rod 176 into the housing 170. This retraction causes the head support portion 14 to pivot about its hinged mounting 80, 82 until it contacts the upper side supports 50, 54. If desired, a stop can be provided to define the lower end point of travel of the head support portion 14. For example, a stop member can be provided to engage the upper part of the cylinder housing 170 when the housing is in the position shown in FIG. 3. However, due to the relatively large surfaces of the side support members 50, 54 of the framework 24 and of the side support members 86, 88 of frame-like carrier 84, no such auxiliary stop has been found to be necessary.

By arresting any further downward deflection of the head support portion 14, the leg support portion 18 pivotally interconnected therewith is fixed in position. Preferably, the hinge connections 80, 82 of the head support portion extend from the central frame 70 which is conveniently made from the same size tubing as the upper side support members 50, 54. With a frame-like carrier 84 of similar cross-sectional dimensions as the vehicular base framework, the desired alignment of the head support portion when in contact with the upper side supports 50, 54 is easily and economically attained. General coplanar alignment of the leg support portion 18 with the remaining support portions 14, 16 is easily attained by adjusting the length of the interconnecting link arms 146, 148.

As briefly mentioned above, the pressure cylinder 168 can be operated in a double-acting mode wherein a pressure fluid is applied to each end of the internal piston to raise and lower the head support portion. However, it is generally preferred to operate the pressure cylinder in a single-action mode wherein an internal spring, such as the spring 171, is disposed within the cylinder housing adjacent the upper end thereof. Upon the application of a pressurized fluid to the lower end of the housing, the work done by the piston 174 not only raises the head support portion 14 and lowers the interconnected foot support portion, but also compresses the internal spring 171, so as to store energy which will later be used when the bed table is returned to its reclined position. In the single-action mode, pressure is applied only to the lower end of cylinder 168, the upper port 175 of the cylinder being utilized to relieve vacuum upon retraction of the piston rod 176, and to relieve back pressure on the piston 174 during extension of the piston rod.

The inclusion of an internal spring augments the pressure imparted to the piston 174, due to the gravity force applied thereto through the pivot connection 162 between the upper end of the piston rod and the head support portion. As can be seen from FIG. 4, the head support portion 14 has a maximum displacement upon raising that stops short of a true vertical position, thereby ensuring a downward gravity component on the piston 174 when retraction thereof is initiated.

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