Electrically Operable Hospital Bed

Abstract

An electrically operable hospital bed having a stationary frame, a relatively movable frame supported on the stationary frame and an articulated mattress support frame secured to the movable frame. The mattress support frame is positionable in a plurality of body supporting positions including elevation of the head end and elevation of the thigh section. Movement of the head end section to inclined body supporting positions causes simultaneous movement of the movable frame and mattress supporting frame toward the head end of the bed. The stationary frame is supported upon the floor by telescoping legs operable through cable mechanism to adjust bed height. A Trendelenburg mechanism is provided to selectively restrain cables associated with head end or foot end legs to accomplish Trendelenburg and reverse Trendelenburg positioning of the bed. An automatic knee-break mechanism selectively provides automatic elevation of the thigh section of the mattress support frame upon elevation of the head section. Selectively activated camming means coact between the stationary frame and the thigh section to provide automatic thigh elevation.

Description

BACKGROUND OF THE INVENTION

This invention relates generally to an electrically operable hospital bed. More particularly, it relates to an electrically operable hospital bed having improved knee contour and Trendelenburg positioning mechanisms.

The present invention is an improved form of electrically operable hospital bed of the type generally shown and described in U.S. Pat. No. 3,237,212, issued March 1, 1966, entitled "Retractable Bed;" U.S. Pat. No. 3,198,891, issued Aug. 3, 1965, entitled "Mechanism for Controlling the Power Unit of an Electric Hospital Bed;" U.S. Pat. No. 3,492,679, issued Feb. 3, 1970, entitled "Trendelenburg Control Mechanism," and U.S. Pat. No. 3,633,225, issued Jan. 11, 1972, entitled "Double Insulated Electric Hospital Bed." The disclosure contained in each of the above-mentioned patents is specifically incorporated by reference to this application.

The bed shown and described in the aforementioned U.S. Pat. No. 3,237,212 represents an important advance in hospital room patient care facilities. The bed includes mechanism for raising the head end of the mattress frame from the horizontal to a plurality of elevated body supporting positions. As the head section is elevated, the entire mattress supporting frame simultaneously moves toward the head end of the bed. In this way, the patient remains in a fixed relationship to auxiliary patient care facilities located adjacent the bed such as the bedside cabinet.

The bed disclosed in U.S. Pat. No. 3,237,212 further includes means for selectively providing automatic elevation of the knee section of the mattress frame as the head section is elevated. In this way, the patient is supported from longitudinal movement toward the foot end of the bed as the head end is elevated. The bed also includes high-low mechanism to vary the position of the mattress frame above the floor. This provides improved versatility in patient ingress and egress and allows for compatibility of the bed height with patient carrying stretchers and other hospital equipment.

The control mechanism illustrated in U.S. Pat. No. 3,198,891 provides the means for actuation of the electrically operable mechanisms of the bed. A reversible electric motor is selectively engageable with one or the other of a pair of screw type actuators supported upon the lower or stationary frame of the bed. One of the actuators is connected to the high-low mechanism to position the bed height with respect to the floor. The other operates appropriate mechanism to raise and lower the head section of the mattress frame.

The Trendelenburg control mechanism disclosed in U.S. Pat. No. 3,492,679 is an improved mechanism for lowering the head end of the mattress frame below the horizontal to provide a modified Trendelenburg position.

U.S. Pat. No. 3,633,225 relates to an improved arrangement for supporting the electrical equipment of the bed upon the bed frame. The invention of this patent provides significant advantages in relation to patient safety. The entire electrical system of the bed is isolated from the bed itself providing a double barrier against dangerous electrical breakdown.

The present invention comprises a further improvement in an electrically operable hospital bed of the type disclosed in the aforementioned patents. It includes improved mechanism for effecting knee lift of the mattress frame as the head end is elevated and it includes improved means for effecting Trendelenburg and reverse Trendelenburg positioning of the mattress frame. These improved mechanisms included improved actuator controls and allow improved control location immediately adjacent the bed operation control levers. These features simplify bed operation to the advantage of the hospital staff. The result is improved patient care services and patient comfort.

SUMMARY OF THE INVENTION

The principal object of the present invention is to provide an improved form of electrically operable hospital bed. The improvements contemplated by the present invention include improved knee-break and Trendelenburg positioning mechanism.

The mechanism for automatic raising of the thigh section of the mattress supporting frame upon elevation of the bed section includes a selectively activated camming means which imparts lifting forces to a lifting arm as the mattress frame moves toward the head end of the bed during head elevation.

The improved means for selective positioning of the bed in the Trendelenburg and reverse Trendelenburg positions operates in cooperation with the high-low mechanism which raises and lowers the entire bed upon telescoping legs. A latch is provided to engage lift cables associated with either leg at the head end or foot end of the bed. The latch is operable only when the bed is in the fully elevated position. Operation of the drive screw to lower the bed causes only the unlatched cables to be effective in lowering the bed, thus providing the desired Trendelenburg or reverse Trendelenburg position.

The operating controls of the bed of the present invention are greatly simplified as a result of incorporation of these new mechanisms in the bed design. Operating handles to provide Trendelenburg positioning or knee-break contour are positioned immediately adjacent the side mounted control handles which operate the normal bed functions.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an electrically operable hospital bed incorporating the features of the present invention.

FIG. 2 is a partially broken away top view of the electrically operable hospital bed of FIG. 1.

FIG. 3 is a side elevational view, partially in section, of the electrically operable hospital bed of FIG. 1.

FIG. 4 is a sectional view of the electrically operable hospital bed of FIG. 1 taken generally along the line 4--4 of FIG. 2.

FIGS. 5 through 8 are fragmentary sectional views of the electrically operable hospital bed of FIG. 1 taken generally along the line 5--5 of FIG. 2, and illustrating the knee-break mechanism of the present invention in various positions of operation.

FIGS. 9 through 11 are fragmentary sectional views of a portion of the electrically operable hospital bed of FIG. 1 taken generally along the line 9--9 of FIG. 2, illustrating the improved Trendelenburg mechanism of the present invention.

FIG. 12 is a sectional view on a slightly enlarged scale of a portion of the electrically operable hospital bed of FIG. 1, illustrating the internal construction of the supporting legs at the head end of the bed.

FIG. 13 is a sectional view on a slightly enlarged scale of a portion of the electrically operable hospital bed of FIG. 1, illustrating the internal construction of the supporting legs at the foot end of the bed.

FIG. 14 is a schematic on a reduced scale illustrating portions of the high-low operating mechanism.

FIG. 15 is a perspective on a slightly enlarged scale of a portion of the electrically operable hospital bed illustrated in FIG. 1.

DETAILED DESCRIPTION

Referring now to the drawings, there is illustrated an electrically operable hospital bed generally designated 10 embodying the principles of the present invention.

The bed 10 includes a high-low or stationary frame 12, an intermediate or longitudinally movable frame 14 and an articulated mattress supporting frame 16 fixed to the intermediate frame.

The stationary frame 12 includes side rails 18 connected at their head and foot end by cross members 20. Each of the side rails 18 include a roller 21 rotatably supported internally of the rails and extending upwardly through an appropriate aperture. These rollers provide support for the movable frame 14. Brackets 15 secured to each side rail overlie the intermediate frame 14 in sliding cooperation. These brackets maintain the frames in alginment and prevent separation of the frames.

The cross members 20 are connected to vertical leg posts 22. These posts are hollow and telescopically support legs 24 which support the bed 10 upon the floor. Operation of the high-low mechanism causes the leg posts 22 to move with respect to the legs 24 to change the bed height with respect to the floor. The legs 24 at the head end of the bed shown in FIG. 12 include a single shaft which telescopes within the post 22. The legs at the foot end shown in FIG. 13 include two sections telescoped within each other. Low friction pads 23 are provided to guide the legs within the posts.

A power and control unit 26 of the type disclosed in aforementioned U.S. Pat. No. 3,198,981 is mounted upon the lower frame of the bed 10. It is supported in the manner disclosed in U.S. Pat. No. 3,633,225 to provide additional safety from electrical hazard.

The control unit includes a reversible electric motor 28, and a control mechanism 32. The unit is operatively associated with a pair of drive screws 34 and 36 rotatably supported upon the stationary frame 12. One of the drive screws 34 is operative to effect simultaneous elevation of the head portion of the mattress support frame 16 and retraction of the seat portion of the mattress support frame toward the head end of the bed.

The drive screw 36 is effective to alter the bed height with respect to the floor. The mechanism which accomplishes this movement is disclosed in the aforementioned U.S. Pat. No. 3,271,795. It includes horizontally supported pulleys 37 mounted upon the stationary frame 12 adjacent the head and foot end and vertically supported pulleys 39 associated with each leg post 22. Flexible cables 41 are connected to the operating nut of the drive screw 36. These cables extend about the pulleys 37 at the head end of the bed, and the pulleys 39 associated with the head end hollow posts and are connected to the top of the head end legs 24, as illustrated in FIG. 12. Flexible cables 43 extend about pulleys 37 at the head end of the bed and then along the entire length of the stationary frame 12 and around pulleys 37 and 39 at the foot end of frame 14. The ends of cables 43 are connected to the tops of legs 24 at the foot end as illustrated in FIG. 13. This cable arrangement is illustrated schematically in FIG. 14.

Operation of drive screw 36 in one direction of rotation causes the operating nut to move toward the head end of the bed. This causes the effective cable length to increase and lower the bed with respect to the legs 24. Operation in the opposite direction causes the nut to move toward the foot end of the bed and decrease the effective cable length. This causes the stationary frame 12 to elevate upon the legs 24.

As best seen in FIGS. 2 and 5 through 8, the lower frame 12 additionally includes a channel 38 extending longitudinally of the bed from approximately the midpoint of the lower frame toward the head end. This channel includes closed end 40 at the lower end opposite the head end of the bed. The channel further defines a planar upper surface 42. This latter surface and the closed end 40 comprise actuator surfaces which coact with the knee-break mechanism of the present invention, as will be explained in further detail.

The intermediate or longitudinally movable frame 14 includes longitudinal side rails 44 connected by transverse channels 46 at the head and foot end. The side rails each included roller 48 rotatably mounted within the side rail and extending through appropriate apertures in the bottom of the rail. These rollers are in rolling supporting contact with the upper surfaces of the side rails 18 of the stationary frame to allow relative longitudinal movement. Brackets 50 secured to the side rails 44 extend downwardly in overlying relation to the inner and bottom surface of the side rails 18. These brackets include low friction pads in sliding contact with the side rails 18 of the stationary frame 12 to guide the moveable frame and prevent transverse movement or separation of the frames.

The mattress supporting frame 16 includes a seat portion 52, a head section 54, a thigh section 56, and a leg or foot section 58.

The seat portion is secured to the intermediate or movable frame for movement longitudinally of the bed by a pair of structural webs 59. The webs extend transversely outwardly of the frames 12 and 14 and terminate a pair of control panels 60 disposed on opposite sides of the bed.

The operator controls of the bed 10 are best illustrated in FIGS. 1, 2 and 3. The controls are accessible on either side of the bed 10 at the control panels 60 of the seat section 52.

Two controls, the head elevation and high-low controls designated 100 and 102, are disposed for patient use. Two others, the automatic knee-break selector 104 and the Trendelenburg position selector 106, are disposed immediately adjacent the patient control, but are disposed out of normal patient reach. Thus, all control functions may be performed at convenient bedside location, yet patient safety is assured through strategic positioning of certain of the levers out of normal patient reach.

The high-low control 102 takes the form of a knob exposed at each of the panels 60. The knobs are connected to a transverse actuator shaft 108 pivotally supported upon the movable frame 14. The shaft 108 is in turn connected through a bell crank and linkage to a longitudinal actuator shaft 110 pivotally supported upon the stationary frame 12. Shaft 110 is of square, cross-section, and the bell crank and linkage arrangement is slidably supported upon the shaft. This is necessary to accomplish transfer of motion through the bell crank and accommodate relative movement between the transverse shaft 108 and longitudinal shaft 110 during relative movement between the stationary and movable frames 12 and 14.

The square shaft 110, best seen in FIG. 15, is connected to the control mechanism through another linkage which actuates the reversing switches and clutch associated with the high-low drive screw 36.

The head elevation control 100 is a wing pivotally supported at its center. It is pivotal downwardly in one direction to elevate the head end and downwardly in the opposite direction to lower the head end. The control is biased to a central neutral position. This arrangement provides a simplified procedure for bed operation and has been found to be readily understood and easily utilized by the patient and hospital staff.

The head elevation wings 102 are operatively connected to a transverse actuator shaft 112 pivotally supported upon the movable frame 14. This shaft is connected through a bell crank and linkage to a longitudinal actuator shaft 114 pivotally supported upon the stationary frame 12. As in the high-low control, the longitudinal shaft 114 is of square, cross-section and the bell crank is slidable upon the shaft to accommodate relative movement between frames 12 and 14.

A bell crank and linkage are connected between the square actuator shaft 114 and the control unit 32 to operate the reversing switches and clutch associated with drive screw 34.

A Trendelenburg selector lever 106 extends downwardly of the web 59 of the seat section 52 at each side of the bed adjacent the control panel 60. The levers are an integral part of a transverse actuator shaft 116 pivotally supported upon frame 14.

The levers 106 are recessed from the outer edge of the bed to avoid accidental actuation or normal use by the patient.

The lever may be moved between a control neutral position which provides normal bed operation or a Trendelenburg and reverse Trendelenburg position to provide selected inclination of the entire bed toward the head end or foot end of the bed.

The transverse actuator shaft 116 is connected to a longitudinal actuator shaft 118 pivotally supported on frame 12 through a bell crank and linkage which is slidable upon shaft 118. As in the case of the high-low and head elevation mechanism, this slidable connection is necessary to accommodate relative movement between the movable and stationary frames. The shaft 118 is in turn connected to the Trendelenburg mechanism through an operating linkage 120 shown in FIGS. 9 through 11.

The automatic knee-break selector 104 comprises a lever extending outwardly of the webs 59 of the seat section 52 at each side of the bed. These levers are disposed at the side of the seat section 52 facing the foot end of the bed, and are recessed from the outer edge of the bed for patient safety. The levers 104 are movable between a position in which the knee-break mechanism is activated for operation and a position in which the knee-break mechanism is deactivated and no knee-break occurs.

The levers 104 are an extension of transverse shaft 122 pivotally supported upon the movable frame 14. As best seen in FIGS. 5 through 8, the transverse shaft 122 is provided with a lever arm 124 extending generally perpendicularly of the shaft. The lever arm includes a roller 126 rotatably supported at its free end which is operatively associated with the knee-break mechanism of the present invention.

Referring again to the mattress support frame 16, head section 54 is pivotally attached to the seat portion 52 at the control panels 60. The head portion includes a transverse bar 62 which supports the head section in a horizontal position upon the intermediate frame 14. A modified Trendelenburg positioning mechanism 63 provided upon the intermediate frame coacts with the bar 62. It allows movement of the head section 54 below the horizontal when desired. This mechanism is described in aforementioned U.S. Pat. No. 3,492,679.

The head section 54 further includes a transverse elevation tube 64 extending downwardly of the section 54. It includes a depending crank arm 66. The crank arm 66 is pivotally connected to the nut of the screw actuator 34. Movement of the nut longitudinally of the bed effects pivotal movement of the head section 54 between the horizontal and inclined body supporting positions.

Links 68 are pivotally connected to the bed section 54 and to the side rail 44 of the intermediate frame 14. Elevation of the head section 54 causes the link to pivot about the connection and draw the intermediate frame longitudinally of the stationaty frame 12 toward the head end of the bed. The patient experiences a constant positioning with respect to auxiliary equipment located adjacent the bed, regardless of the degree of head section elevation. Similarly, as the screw 34 is operated to lower the head section toward horizontal, the links 68 cause the entire intermediate frame and mattress frame to move longitudinally toward the foot end of the bed.

The thigh section 56 is pivotally connected to the seat section webs at the control panel 60. It includes a transverse elevation tube 70 which extends downwardly toward the movable frame 14. A depending crank arm 72 is secured to the tube 70. The lowermost end of the crank arm 72 is provided with a roller 74 which forms a portion of the knee-break mechanism of the present invention, as will be explained in further detail shortly.

The crank arm 72 and transverse elevation tube 70 comprise a lever for elevation of the thigh section of the mattress frame 14. When desired, elevation of the thigh section is accomplished automatically during elevation of the head section 54 by the knee-break mechanism of the present invention, as will be explained.

The thigh section may also be elevated normally regardless of the position of the head section when such positioning is necessary for patient comfort or treatment. This is accomplished through the manual crank 76 provided at the foot end of the bed. The crank 76 is connected to a screw type actuator 78 supported upon the movable frame 14.

The operating nut of the actuator 78 is operatively connected to the crank arm 72 by pivotally connected link 80 shown in FIGS. 2 and 5 through 7. As the operating nut is drawn toward the foot end of the bed by rotation of the manual crank 76, the links 80 pull upon the crank arm 72 causing pivotal movement of the thigh section about its connection to the seat portion 52. The links 80 include lost motion slots 82 at the connection to the crank arm 72 to allow operation of the thigh section by the actuator knee-break mechanism without interference by the manual crank 76.

The foot or leg section 58 is pivotally connected to the thigh section 56 as at 84. The free end of the foot section 58 adjacent the foot end of the bed is supported upon two depending links 86 pivotally connected to the foot section. The links 86 include free ends provided with a plurality of notches 88. These notches are adapted for engagement with brackets 90 provided upon the intermediate frame 14.

The elevation of the foot section of the frame 16 may be varied manually by positioning different notches in engagement with the brackets 90. In addition, as the thigh section 56 of the mattress frame is elevated, the links 86 pivot upon the brackets 90 to effect elevation of the foot position. To further elevate the foot section, the links are moved to engage notches nearer the free ends of the links with the brackets. To lower the foot section, the notches 88 furthest from the free ends of the links are engaged with the brackets 90.

Support bars 91 extending transversely of the thigh section 56 and foot section 58 normally support these sections in the horizontal body supporting position. These bars normally rest upon a cover member (not shown) which overlies the power and control unit 26.

In accordance with the present invention, the bed 10 includes an automatic knee-break mechanism generally designated 150, best seen in FIGS. 5 through 8. The mechanism may be activated to provide automatic elevation of thigh section 56 as the head section 54 is inclined, or it may be deactivated to exclude the function. Selection is made through positioning of the selector 104. When the selector is in the position illustrated in FIG. 5, no thigh elevation takes place. When positioned as in FIGS. 6 through 8, the mechanism is activated to accomplish knee-lift.

The automatic knee-break mechanism includes two plates pivotally supported upon the movable frame 14. These plates comprise an operator plate 152 and a cam plate 154 pivotally connected to the frame 14 upon a common shaft 155.

The operator plate 152 is biased toward the head end of the bed by spring 149 connected between the plate and shaft 108. The plate defines a notch 156 which receives the roller 126 mounted on the lever arm 124. The spring bias maintains operative contact between the roller 124 and notch 156.

The notch 156 defines an activated position 157 and a deactivated position 158. Movement of the roller 126 between these two positions by movement of lever 104 changes the angular position of the operator plate as illustrated in the drawings. the plate 152 further includes a tab 159 which extens transversely outwardly of the plate in spaced relation to the shaft 155. The position of this tab controls operation of the cam plate 154 as will be explained.

The cam plate 154 is spring biased toward the head end of the bed by spring 160 extending between the plate 154 and web 59. The plate defines a stop 162 adapted to engage tab 159 of operator plate 152 to prevent rotation of the plate 154 about the common shaft 155. It further defines a cam surface 164 adapted for coaction with roller 74 mounted on crank arm 72 of the thigh section 56 to accomplish thigh section elevation.

The cam plate 154 is provided with a roller 166 adapted for coaction with channel 38 mounted on stationary frame 12 to render cam surface 164 effective to elevate the thigh section 56 when lever 104 is in the activated position. In FIG. 5, the automatic knee-break mechanism 150 is illustrated in the deactivated position. That is, inclination of the head section 54 of the mattress supporting frame 16 and retraction of the seat section 52 toward the head end of the bed will produce no automatic knee elevation. As explained, however, knee elevation may be provided manually through operation of crank 76.

In the position illustrated in FIG. 5, selector lever 104 is positioned such that roller 126 on arm 124 is disposed in the deactivated position 158 of notch 156. In this position, the plate 152 is urged against the bias of spring 149 to a position where tab 159 is rotated to a predetermined inclined angle toward the foot end of the bed.

Biasing spring 160 causes the cam plate 154 to rotate about shaft 155 until stop 162 engages tab 159. Tab 159, therefore, determines the positioning of cam plate 154 when the plate is under control of biasing spring 160.

In the position described, the cam plate is urged to a position against tab 159 where roller 166 is disposed above channel 38. As the head section 52 of the mattress support frame 16 is elevated, the knee-break mechanism 150 passes over the channel 38 due to relative movement between frame 12 and 14. No contact is made between roller 166 and channel 38 and no knee elevation occurs.

To provide automatic knee-break or thigh elevation, selector lever 104 is moved to the position illustrated in FIGS. 6 through 8. During this movement, biasing spring 149 allows the actuator plate 152 to rotate about shaft 155 while allowing notch 156 and roller 126 to remain in operative contact. This movement continues until roller 126 becomes disposed in the activated position 158 of the notch 156. The resultant angular change of position places tab 159 in a nearly vertical position.

Rotational movement of the operator plate 152 is transferred to the cam plate through the contact between tab 159 and stop 162. This movement rotates the cam plate 154 against the bias of spring 160 to a position where the roller 166 becomes disposed below the surface 42 of channel 40.

Elevation of head section 54 of the mattress support frame 16 causes movement of the intermediate frame 14 toward the head end of the bed. This movement causes engagement of roller 166 with closed end 40 of channel 38 mounted on the stationary frame 12 as best seen in FIG. 6.

As the elevation of head section 54 continues, frame 14 continues to move toward the head end of the bed. The coaction between roller 166 and closed end causes cam plate 154 to rotate against the bias of the spring 160. This movement, in turn, causes stop 162 to separate from tab 159 and causes cam surface 164 to move into contact with roller 74 mounted on crank arm 72. Continued operation of the head elevation mechanism causes further camming of cam plate 154 in a direction toward roller 74. As shown in FIG. 7, the coaction between cam surface 164 and roller 74 applies a lifting force to crank arm 72 and causes thigh section 56 to pivot about its connection to the seat section.

This lifting movement continues as the frame 14 moves toward the head end of the bed and continued rotation of cam plate 154 occurs.

When the bed mechanism has reached the position illustrated in FIG. 8, maximum thigh elevation is provided. Roller 166 is in engagement with the upper surface 42 of channel 38. The cam plate 154 has been pivoted about the shaft 155 to a maximum separation between stop 162 and tab 159. Thigh section 56 is now elevated to the maximum position.

Further elevation of the head end of the bed and consequent relative movement of the frame 14 with respect to stationary frame 12, does not change the angular position of cam plate 154. This is true since roller 166 is progressing along the horizontal surface 42. Thus, the position of cam surface 164 remains constant and no further elevation of the thigh section 56 occurs.

It has been determined that a desirable maximum thigh section elevation provided by the automatic knee-lift mechanism is 15.degree. from horizontal. The camming surfaces are sized and positioned such that this maximum is achieved when the head section has reached an elevation of 35.degree.. Thereafter, as the head section is elevated to its maximum position, no further thigh section elevation occurs. These positions are not critical to the present invention and are only considered as desirable for patient comfort.

Should further thigh section elevation be required, the crank arm 72 may be operated through links 80 by the manual crank 76. Depending upon the position of the drive screw operating nut, operation of the crank 76 will first take up any lost motion provided by slots 82. Thereafter, the links 80 will pull the crank 72 in a direction to separate roller 74 from cam surface 164 and further elevate the thigh section.

One important feature of the automatic knee-break mechanism 150 of the present invention is that the selector lever 104 may be moved between the activated and deactivated position at any time. When the head section 54 is horizontal, as in FIG. 5, the roller 166 is spaced from channel 38. Therefore, movement of the lever 104 to the activated position rotates the cam plate 154 to the operative position.

When in the operative position and the head section 54 is elevated even slightly, the position of the cam plate 154 is determined by the contact between the roller 166 and the surface 40 or 42. Tab 159 and stop 162 are not in contact. Movement of the lever 104 to the deactivated position merely rotates tab 159 in a direction to increase the space between the tabs and stop 162 without disturbing the position of cam plate 152. Upon movement of the head section 54 to the horizontal position, the cam plate will be urged into contact with the tab 159 by the biasing spring 160. The cam plate will, therefore, assume the deactivated position illustrated in FIG. 5. Upon subsequent elevation of the head section 54, the thigh section 56 will remain in the horizontal position.

Another important feature of the bed of the present invention is the Trendelenburg and reverse Trendelenburg positioning mechanism. The mechanism generally designated 200 operates in cooperation with the high-low mechanisms which provides for adjustment of bed height.

The mechanism 200 is selectively operable, utilizing selector lever 106. It is effective to provide inclination of the entire bed 10, including stationary frame 12, movable frame 14 and mattress supporting frame 16 in either a head end down (Trendelenburg) or a foot end down (reverse Trendelenburg) position.

The Trendelenburg mechanism 200, best seen in FIGS. 3 and 9 through 11, includes a Trendelenburg hook member 202 pivotally supported upon the stationary frame 12 and a pair of hook receptacles 204 and 206 associated, respectively, with the head end leg cables 41 and foot end leg cables 43.

The hook member 202 is supported upon the stationary frame 12 in surrounding relation to drive screw 36 of the high-low operating mechanism by a bracket 212. The bracket is generally U shaped with one leg of the "U" disposed on either side of the drive screw. Two horizontal cross pins 201 are connected between the legs of the U-shaped bracket 212 in general vertical alignment, one above drive screw 36 and one below.

Similarly, and as best seen in FIG. 2, the hook member 202 is also formed of a channel or U-shaped member. The hook member is disposed with one leg of the "U" located on either side of drive screw 36. Each leg of the hook member is provided with a pair of elongated slots 216 which receive cross pins 201. This provides for pivotal support of the member 201 on the bracket 212. The separate legs of the hook member are joined by two cross webs 214, one at the top of the member and one at one end, above drive screw 36. Three notches 203 are provided across the top of the member for purposes as will be explained.

Each leg of the hook member 202 defines a Trendelenburg claw 208 and a reverse Trendelenburg claw 210. Thus, two claws are defined for each position, one on either side of drive screw 36. The Trendelenburg hook member 202 is spring biased by a apir of springs 218, one on each side of bracket 212. It is pivotal between three positions of operation, neutral, as illustrated in FIG. 9, Trendelenburg, as illustrated in FIG. 10, and reverse Trendelenburg, as illustrated in FIG. 11. The spring bias assists to maintain the hook in position.

Positioning of the Trendelenburg hook member is accomplished through the selector lever 106. Movement of the lever 106 is transferred through transverse shaft 116 and longitudinal shaft 118 and operating linkage 120.

This linkage includes a generally vertical link 220 and a generally horizontal lever arm 221 shown in cross-section in FIGS. 9 through 11. The lever arm 221 is fixed to longitudinal shaft 118. It is shaped to pass beneath longitudinal shaft 110 associated with the high-low actuating mechanism and connects to vertical link 220 at its upper end.

Movement of selector lever 106 in one direction causes pivotal movement of shaft 118 in a direction to create an upward pull on link 220 through lever arm 221. This pivots hook member 202 downwardly. Movement of selector lever 106 in the opposite direction causes pivotal movement of longitudinal shaft 118 in the opposite direction. This causes lever arm 221 to push downwardly upon link 220 and pivots member 202 upwardly.

The cables 41 and 43 associated with telescoping legs 24 are connected to the operating nut of drive screw 36. As can be appreciated, the position of the operating nut along the drive screw determines the bed height. That is, as the nut is moved toward the foot end of the bed, the effective length of the cables is reduced, causing the bed to elevate upon legs 24. When the nut reaches the end of the drive screw nearest the foot end of the bed, the legs 24 are fully extended and the bed is at maximum height. As the nut is moved toward the head end of the bed, the effective length of cables 41 and 43 is increased. The weight of the bed causes it to move downwardly upon the legs 24 to accommodate the increased cable lengths.

The cable pairs 41 and 43 are connected to the operating nut of the drive screw 36 in a manner such that the nut may move with respect to the cables during Trendelenburg positioning. The cable pairs pass through apertures 223 formed in the nut and are connected to the hook receptacles 204 and 206 by fastener 224. Each fastener includes a guide pin portion that is adapted to be slidingly received in the associated aperture.

Each hook receptacle 204 and 206 includes a generally vertical plate portion 226 which is adapted for abutting engagement with the nut. This abutting engagement prevents the cables to withdraw from the nut and comprises the connection between the cables and the nut.

The hooks 204 and 206 further include generally horizontal receptacle defining portions 227 which extend toward the foot end of the bed. Each defines an aperture, as best seen in FIG. 2, adapted to receive the associated claws 210 and 212 of the hook member 202.

When the bed is at the maximum height above the floor, the hook receptacles 204 and 206 are positioned between the claws 208 and 210 of the member 202. Movement of the selector lever 106 to either the Trendelenburg or reverse Trendelenburg selector position will cause the member 202 to be pivoted in the appropriate direction and one or the other of the pairs of claws 208 or 210 will be disposed within the receptacle defining aperture of the associated receptacle 204 or 206. Thereafter, upon operation of the high-low mechanism 100 to lower the bed upon legs 24 and movement of the drive screw operating nut toward the head end of the bed and interengaged claw and receptacles will prevent one of the pairs of cables 41 or 43 to extend. That pair of cables will remain stationary and the height of the bed at the affected end of the bed will remain maximum. The other, unlatched receptacle, will follow the drive screw nut and that pair of cables will operate to lower the opposite end of the bed.

To provide Trendelenburg positioning, the selector lever 106 is positioned to move claw 208 into engagement with receptacle 206 as illustrated in FIG. 10. This prevents extension of cable 43 associated with foot end legs 24. Operation of the high-low mechanism is effective only with respect to cables 41 and only the head end of the bed will lower on the telescoping legs.

To provide reverse Trendelenburg positioning, the selector lever is moved to position member 202 as illustrated in FIG. 11 with claw 210 in engagement with receptacle 204. Upon actuation of the high-low mechanism, only cables 43 will be extended, lowering the foot end of the bed.

For patient safety, the claws 208 and 210 are sized and shaped such that only a positive engagement of the receptacles can be achieved upon operation of the Trendelenburg selector and only when the bed is at maximum elevated height. Also, since the one or the other ends of the bed are held in maximum up position upon the telescoping legs, the engagement between claw and receptacles carries approximately one-half the bed weight. The shape of the claws and the weight applied to the cables prevents operation of the selector lever 106 and accidental disengagement of the claw and receptacle, while the bed is in any position of Trendelenburg.

A further safety feature operation of the high-low mechanism except when the Trendelenburg selector is in either the neutral, Trendelenburg, or reverse Trendelenburg position. The longitudinal shaft 110 which is connedted to the high-low operating control 100 is provided with a depending web 229. The web in sized and positioned such that when the shaft 110 is pivoted upon actuation of the control the web is moved into coaction with the member 202. When the member 202 is in the neutral, Trendelenburg or reverse Trendelenburg positions, actuation of the high-low control will cause the web 229 to pass within one of the notches 203 formed in the hook member and operation is not impaired. However, if the hook member is positioned in any intermediate position, the web 229 will engage the leg of the member 202 and pivotal movement of the shaft 110 will be prevented, and the drive screw 36 will not be energized. This prevents operation of the high-low mechanism at any time other than when claws 208 and 210 and receptacles 204 and 206 are fully latched or unlatched.

As can be seen, an improved form of electrically operable hospital bed has been provided having improved knee contour and Trendelenburg positioning mechanisms. The bed also provides improved control locations resulting in improved patient care capabilities.

Various features of the present invention have been particularly shown and described. However, it should be understood that various modifications may be made without departing from the spirit and scope of the present invention.

Claims

What is claimed is:

1. In an electrically operable hospital bed having a stationary frame supporting said bed upon the floor, a relatively movable frame supported by said stationary frame and movable with respect thereto, an articulated mattress support frame secured to said movable frame for movement therewith including a thigh portion pivotal between a plurality of thigh supporting positions, the improvement comprising camming means operatively associated with said thigh section and secured to one of said stationary and movable frames and positionable to engage the other thereof, said camming means being responsive to the relative movement between said movable and stationary frames to effect positioning of said thigh section when in said position to engage said one of said stationary and movable frames.

2. The improvement as claimed in claim 1 wherein said thigh section includes a crank arm connected thereto adapted to receive lifting forces from said camming means and said camming means includes a cam plate pivotally supported upon said movable frame for movement into contact with said crank arm to effect positioning of said thigh section, and means on said stationary frame operatively associated with said cam plate for moving said cam plate into operative association with said crank arm during movement of said movable frame.

3. The improvement as claimed in claim 2 wherein said stationary frame includes a generally horizontally disposed channel having a planar upper surface and closed end facing said camming means, and wherein said cam plate includes a roller adapted to contact said closed end and planar upper surface of said channel to pivot said cam plate into contact with said crank arm during movement of said movable frame.

4. The improvement as claimed in claim 1 wherein said bed includes control means carried by said movable frame to selectively activate and deactivate said camming means, said control means including an operator plate pivotally supported upon said movable frame in operative association with said cam plate and including a tab engageable by said cam plate, said operator plate being positionable to move said tab between a first and second position and biasing means urging said cam plate toward engagement with said tab, said cam plate being positioned by said operator plate when said operator plate is in said first position such that no engagement occurs between said roller and channel upon movement of said movable frame and said cam plate being positioned for engagement of said roller with said channel when said operator plate is in said second position.

5. The improvement as claimed in claim 4 wherein biasing means connected to said operator plate urge said plate toward said tab with said cam plate, and said control means include means for pivoting said operator plate between said first and second positions, said biasing means allows said pivotal movement regardless of the position of said cam plate.

6. In an electrically operable hospital bed having a frame, pairs of legs at the head end and foot end of said frame supporting said frame upon the floor, said legs being telescopable with respect to said frame to adjust the height of said frame above the floor, cable pairs carried by said frame connected respectively to said telescopable legs at the head end and foot end of said frame, the effective length of said calbes being adjustable to vary bed height, and electrically operable means connected to said cable pairs for varying said cable length, the improvement comprising Trendelenburg positioning means mounted on said frame in operative association with said cable pairs, said means being selectively operable to secure selected ones of said pairs of said cables to fix the effective length thereof and render said length varying means inoperative with respect thereto.

7. The improvement as claimed in claim 6 wherein said Trendelenburg positioning means includes a hook member mounted on said frame and movable between neutral, Trendelenburg and reverse Trendelenburg positions, said cable pairs each include a receptacle plate connected to their free ends for movement of said hook member into said Trendelenburg position causing engagement of said hook with said receptacle connected to the cable pairs connected to the legs at the foot end of the frame and movement of said hook into said reverse Trendelenburg position causes engagement of said hook with said receptacle connected to said cable pairs connected to said legs at said head end of said frame.

8. The improvement as claimed in claim 7 wherein said cable length varying means includes a screw type actuator having a drive nut movable longitudinally of the bed, said drive nut includes a plurality of apertures each slidably receiving one of said cables, said cables passing through said apertures and being connected to said receptacles, said receptacles adapted for abutting engagement with said nut, positioning of said mechanism in said neutral position allowing said receptacles to remain in said abutting contact during operation of said drive screw, positioning of said mechanism in said Trendelenburg position causing said cable pair connected to said foot end legs to remain fixed and said nut to move with respect to said cables, and positioning of said mechanism in said reverse Trendelenburg position causing said cable pair connected to said head end legs to remain fixed and said nut to move with respect thereto.

9. The improvement as claimed in claim 8 wherein said hook includes a plurality of notches and said electrically operable means includes actuator means including a shaft pivotally movable to effect actuation of said drive screw, said shaft including an outwardly extending web position for pivotal movement into said notches when said hook is in said neutral, Trendelenburg or reverse Trendelenburg position, said web engaging said hook to prevent pivotal movement of said shaft when said hook is in any intermediate position.

10. The improvement as claimed in claim 8 wherein said hook includes a plurality of notches, and said electrically operable means for operation of said drive screw includes a shaft pivotally movable to effect operation including a web extending therefrom.

11. A patient control actuator for an electrically operable hospital bed comprising, a member having a pivotal mounting upon a hospital bed, said member having a central hub coincident with said pivotal mounting and having a pair of divergent, outwardly directed actuator wings extending from said hub for receiving pivotal force to pivot said member about said pivotal mounting between a neutral position, a first operative position by pivoting in a first direction from said neutral position and a second operative position by pivoting in a second direction from said neutral position.

12. A patient control actuator as claimed in claim 11 wherein said member is biased to said neutral position.

13. In an electrically operable hospital bed as claimed in claim 1 wherein said hospital bed further includes a pair of legs at the head end and foot end of said frame supporting said bed upon the floor, said legs being telescopable with respect to said frame to adjust the height of said frame above the floor, cable pairs carried by said frame and connected respectively to said telescopable legs at the head end and foot end of said frame, the effective length of said cable pairs being adjustable to vary bed height and electrically operable means connected to said cable pairs for varying said cable length, the improvement comprising Trendelenburg positioning means mounted on said frame in operative association with said cable pairs, said means being selectively operable to secure selective ones of said pairs of said cables to fix the effective length thereof and render said length varying means inoperative with respect thereto.