US3821821A - Electrically operable hospital bed - Google Patents

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

United States Patent 1191 11] 3,821,821 Burst et al. July 2, 1974 ELECTRICALLY OPERABLE HOSPITAL [57] ABSTRACT 7 BED An electrically operable hospital bed having a station- [75] Inventors: Francis J. Burst, Batesville; Daniel ary frame, a relanvely movabl? frame supported on R Tekulve, Oldenburg; James the stationary frame and an articulated mattress sup- Adams, Batesville allf 1 port frame secured to the movable frame. The mattresssupport frame is positionable in a plurality of [73] Asslgneei Company Inc-1 Batesvlne body supporting positions including elevation of the head end and elevation of the thigh section. Move- [22 i 21, 1972 ment of the head end section to inclined body sup- 1 porting positions causes simultaneous movement of [21] Appl' 282,177 the movable frame and mattress supporting frame toward the head end of the bed. [52] U.S. Cl. 5/68, 5/66 The stationary frame is supported upon the floor by [51] Int. Cl A6lg 7/10, A47c 3/32 telescoping legs operable through cable mechanism to [58] Field of Search 5/63, 69; 200/5 adjust bed height. A Trendelenburg mechanism is provided to selectively restrain cables associated with [56] References Cited head end or foot end legs to accomplish UNITED STATES PATENTS Trendelenburg and reverse Trendelenburg positioning 1,908,530 5/1933 Nixon et al. 5/68 x of the 3,237,212 3/l966 Hillenbrand et al. 5/68 An automatic knee-break mechanism selectively 3,414,913 12/1968 Stanley 818.1. 5/68 provides automatic elevation 0f the ection of I the mattress support frame upon elevation of the head 1 e section. Selectively activated .camming means coact 3,633,225 1/1972 Burst et al. 5/68 between the stationary frame and the thigh section to Primary Examiner casmir A Nunberg provide automatic thigh elevation.

13 Claims, 15 Drawing Figures 68 ma go/5 52s6 16 112104 56 1 22 oM I 1 91 IO 11loo 1 22 111 \i 84 110 114 2B 44 Z I 118v 1 1 at e i 18 1oz I 2o 104 24 44 as 3s 22 ,l 20 14 PATENFEB L 21914 3821 821 SHEET 2 OF 6 HCO 0 1' @Hr n EATENTED 21974 $3,821,821

SHEET h BF 6 ELECTRICALLY OPERABLE HOSPITAL BED 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 US. Pat. No. 3,237,2l2, issued March 1, 1966, entitled Retractable Bed; US. Pat. No. 3,198,891, issued Aug. 3, 1965, entitled Mechanism for Controlling the Power Unit of an Electric Hospital Bed; US. Pat. No. 3,492,679, issued Feb, 3, 1970, entitled Trendelenburg Control Mechanism, and US. Pat. No. 3,633,225, issued Jan. 11, 1972, entitled Double Insulated Electric Hospital Bed. The disclosure contained in each of the abovementioned patents is specifically incorporated by reference to this application.

The bed shown and described in the aforementioned US. 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 US. 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 US. 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 US. 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 theunlatched 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 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 embodying the principles of the present invention.

Thebed 10 includes a high-low orstationary frame 12, an intermediate or longitudinallymovable frame 14 and an articulatedmattress supporting frame 16 fixed to the intermediate frame.

I Thestationary frame 12 includes side rails 18 connected at their head and foot end bycross members 20. Each of the side rails 18 include aroller 21 rotatably supported internally of the rails and extending upwardlythrough an appropriate aperture. These rollers provide support for themovable frame 14. Brackets secured to each side rail overlie the intermediate frame 14in sliding cooperation. These brackets maintain the frames in alginment and prevent separation of the frames.

, The cross members are connected to vertical leg posts 22. These posts are hollow and telescopically supportlegs 24 which support thebed 10 upon the floor. Operation of the high-low mechanism causes the leg posts 22 to move with respect to thelegs 24 to change the bed height with respect to the floor. Thelegs 24 at the head end of the bed shown in FIG.'12 include a single shaft which telescopes within thepost 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 andcontrol unit 26 of the type disclosed in aforementioned U.S. Pat. No. 3,198,981 is mounted upon the lower frame of thebed 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 reversibleelectric motor 28, and acontrol mechanism 32. The unit is operatively .associated with a pair of drive screws 34 and 36 rotatably supported upon thestationary frame 12. One of the drive screws 34 is operative to effect simultaneous elevation of the head portion of themattress support frame 16 and retraction of the seat portion of the mattress support frame toward the head end of the bed.

Thedrive screw 36 is effective to alter the bed height with-respect to the floor. The mechanism which accomplishes this movement is disclosed in the aforementrated in FIG. 12.Flexible cables 43 extend aboutpulleys 37 at the head end of the bed and then along the entire length of thestationary frame 12 andaround pulleys 37 and 39 at the foot end offrame 14. The ends ofcables 43 are connected to the tops oflegs 24 at the foot end as illustrated in FIG. 13. This cable arrange- -ment is illustrated schematically in FIG. 14.

Operation ofdrive 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 thelegs 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 thestationary frame 12 to elevate upon thelegs 24.

As best seen in FIGS. 2 and 5 through 8, thelower frame 12 additionally includes achannel 38 extending longitudinally of the bed from approximately the midpoint of the lower frame toward the head end. This channel includesclosed end 40 at the lower end opposite the head end of the bed. The channel further defines a planarupper surface 42. This latter surface and theclosed 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 longitudinallymovable frame 14 includes longitudinal side rails 44 connected by transverse channels 46 at the head and foot end. The side rails each includedroller 48 rotatably mounted within the side rail and extending through appropriate aper tures 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 thestationary frame 12 to guide the moveable frame andprevent transverse movement or separation of the frames.

Themattress supporting frame 16 includes aseat portion 52, ahead section 54, athigh section 56, and v a leg orfoot section 58.

Theseat portion is secured to the intermediate or movable frame for movement longitudinally of the bed by a pair of structural webs S9. The webs extend transversely outwardly of theframes 12 and 14 and terminate a pair ofcontrol panels 60 disposed on opposite sides of the bed.

The operator controls of thebed 10 are best illustrated in FIGS. 1, 2 and 3. The controls are accessible on either side of thebed 10 at thecontrol panels 60 of theseat section 52.

Two controls, the head elevation and high-low controls designated and 102, are disposed for patient use. Two others, the automatic knee-break selector 104 and theTrendelenburg 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 thepanels 60. The knobs are connected to atransverse actuator shaft 108 pivotally supported upon themovable frame 14. Theshaft 108 is in turn connected through a bell crank and linkage to alongitudinal actuator shaft 110 pivotally supported upon thestationary 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 thetransverse shaft 108 andlongitudinal shaft 110 during relative movement between the stationary andmovable frames 12 and 14.

Thesquare 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.

Thehead 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.

Thehead elevation wings 102 are operatively connected to atransverse actuator shaft 112 pivotally supported upon themovable frame 14. This shaft is connected through a bell crank and linkage to alongitudinal actuator shaft 114 pivotally supported upon thestationary frame 12. As in the high-low control, thelongitudinal shaft 114 is of square, cross-section and the bell crank is slidable upon the shaft to accommodate relative movement betweenframes 12 and 14.

A bell crank and linkage are connected between thesquare actuator shaft 1 14 and thecontrol unit 32 to operate the reversing switches and clutch associated withdrive screw 34.

ATrendelenburg selector lever 106 extends downwardly of theweb 59 of theseat section 52 at each side of the bed adjacent thecontrol panel 60. The levers are an integral part of atransverse actuator shaft 1 16 pivotally supported uponframe 14.

Thelevers 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.

Thetransverse actuator shaft 116 is connected to alongitudinal actuator shaft 118 pivotally supported onframe 12 through a bell crank and linkage which is slidable uponshaft 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. Theshaft 118 is in turn connected to the Trendelenburg mechanism through anoperating linkage 120 shown in FIGS. 9 through 11.

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

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

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

about the connection and draw the intermediate frame longitudinally of thestationaty 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 thescrew 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.

Thethigh section 56 is pivotally connected to the seat section webs at thecontrol panel 60. It includes atransverse elevation tube 70 which extends downwardly toward themovable frame 14. A dependingcrank arm 72 is secured to thetube 70. The lowermost end of thecrank arm 72 is provided with aroller 74 which forms a portion of the knee-break mechanism of the present invention, as will be explained in further detail shortly.

Thecrank arm 72 andtransverse elevation tube 70 comprise a lever for elevation of the thigh section of themattress frame 14. When desired, elevation of the thigh section is accomplished automatically during ele vation of thehead section 54 by the knee-break mechanism of the present invention; as will be explained.

anism is activated for operation and a position in which 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. Thecrank 76 is connected to ascrew type actuator 78 supported upon-themovable frame 14.

The operating nut of theactuator 78 is operatively connected to thecrank arm 72 by pivotally connectedlink 80 shown in FIGS. 2 and 5 through 7. Astheoperthe thigh section 56 as at 84. The free end of thefoot section 58 adjacent the foot end of the bed is supported upon two dependinglinks 86 pivotally connected to'the foot section. Thelinks 86 include free ends provided with a plurality ofnotches 88. These notches are adapted for engagement withbrackets 90 provided upon theintermediate frame 14.

The elevation of the foot section of theframe 16 may be varied manually by positioning different notches in engagement with thebrackets 90. In addition, as thethigh section 56 of the mattress frame is elevated, thelinks 86 pivot upon thebrackets 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, thenotches 88 furthest from the free ends of the links are engaged with thebrackets 90.

1 In accordance with the present invention, the bed includes an automatic kneebreak mechanism generally designated 150, best seen in FIGS. 5 through 8. The mechanism may be activated to provide automatic elevation ofthigh section 56 as thehead section 54 is inclined, or it may be deactivated to exclude the function. Selection is made through positioning of theselector 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 themovable frame 14. These plates comprise anoperator plate 152 and acam plate 154 pivotally connected to theframe 14 upon acommon shaft 155.

Theoperator plate 152 is biased toward the head end of the bed byspring 149 connected between the plate andshaft 108. The plate definesanotch 156 which receives theroller 126 mounted on thelever arm 124. The spring bias maintains operative contact between theroller 124 and notch 156.

Thenotch 156 defines an activatedposition 157 and a deactivatedposition 158. Movement of theroller 126 between these two positions by movement oflever 104 changes the angular position of the operator plate as illustrated in the drawings. theplate 152 further includes atab 159 which extens transversely outwardly of the plate in spaced relation to theshaft 155. The-position of this tab controls operation of the cam plate end of the bed byspring 160 extending between theplate 154 andweb 59.'The plate defines a stop 162 adapted to engagetab 159 ofoperator plate 152 to prevent rotation of theplate 154 about thecommon shaft 155. It further defines acam surface 164 adapted for coaction withroller 74 mounted on crankarm 72 of thethigh section 56 to accomplish thigh section elevation.

Thecam plate 154 is provided with aroller 166 adapted for coaction withchannel 38 mounted onstationary frame 12 to rendercam surface 164 effective to elevate thethigh section 56 whenlever 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 thehead section 54 of themattress supporting frame 16 and retraction of theseat 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 ofcrank 76.

In the position illustrated in FIG. 5,selector lever 104 is positionedsuchthat roller 126 on arm '124 is disposed in the deactivatedposition 158 ofnotch 156. In this position, theplate 152 is urged against the bias ofspring 149 to a position wheretab 159 is rotated to a predetermined inclined angle toward the foot-end of the bed.

Biasing spring 160 causes thecam plate 154 to rotate aboutshaft 155 until stop 162 engagestab 159.Tab 159, therefore, determines the positioning ofcam plate 154 when the plate is under control of biasingspring 160.

In the position described, the cam plate is urged to a position againsttab 159 whereroller 166 is disposed abovechannel 38. As thehead section 52 of themattress support frame 16 is elevated, the knee-break mechanism passes over thechannel 38 due to relative movement betweenframe 12 and 14. No contact is made betweenroller 166 andchannel 38 and no knee elevation occurs. 7 g

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, biasingspring 149 allows theactuator plate 152 to rotate aboutshaft 155 while allowingnotch 156 androller 126 to remain in operative contact. This movement continues untilroller 126 becomes disposed in the activatedposi tion 158 of thenotch 156. The resultant angular change ofposition places tab 159 in a nearly vertical position.

Rotational movement of theoperator plate 152 is transferred to the cam plate through the contact betweentab 159 and stop 162. This movement rotates thecam plate 154 against the bias ofspring 160 to a position where theroller 166 becomes disposed below thesurface 42 ofchannel 40.

Elevation ofhead section 54 of the mattress support frame l6causes movement of theintermediate frame 14 toward the head end of the bed. This movement causes engagement ofroller 166 withclosed end 40 ofchannel 38 mounted on thestationary frame 12 as best seen in FIG. 6. l

As the elevation of head section '54 continues,frame 14 continues to move toward the head end' of the bed. The coaction betweenroller 166. and closed end causescam plate 154 to rotate against the bias of thespring 160. This movement, in turn, causes stop 162 to separate fromtab 159 and causescam surface 164 to move into contact withroller 74 mounted on crankarm 72. Continued operation of the head elevation mechanism causes further camming ofcam plate 154 in a direction towardroller 74. As shown in FIG. 7, the coaction betweencam surface 164 androller 74 applies a lifting force to crankarm 72 and causesthigh section 56 to pivot about its connection to the seat section.

This lifting movement continues as theframe 14 moves toward the head end of the bed and continued rotation ofcam 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 theupper surface 42 ofchannel 38. Thecam plate 154 has been pivoted about theshaft 155 to a maximum separation between stop 162 andtab 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 theframe 14 with respect tostationary frame 12, does not change the angular position ofcam plate 154. This is true sinceroller 166 is progressing along thehorizontal surface 42. Thus, the position ofcam surface 164 remains constant and no further elevation of thethigh section 56 occurs.

It has been determined that a desirable maximum thigh section elevation provided by the automatic knee-lift mechanism is 15 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. 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, thecrank arm 72 may be operated throughlinks 80 by the manual crank 76. Depending upon the position of the drive screw operating nut, operation of thecrank 76 will first take up any lost motion provided byslots 82. Thereafter, thelinks 80 will pull thecrank 72 in a direction to separateroller 74 fromcam surface 164 and further elevate the thigh section.

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

When in the operative position and thehead section 54 is elevated even slightly, the position of thecam plate 154 is determined by the contact between theroller 166 and thesurface 40 or 42.Tab 159 and stop 162 are not in contact. Movement of thelever 104 to the deactivated position merely rotatestab 159 in a direction to increase the spacebetween the tabs and stop 162 without disturbing the position ofcam plate 152. Upon movement of thehead section 54 to the horizontal position, the cam plate will be urged into contact with thetab 159 by the biasingspring 160. The cam plate will, therefore, assume the deactivated position illustrated in FIG. 5. Upon subsequent elevation of thehead section 54, thethigh 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 highlow mechanisms which provides for adjustment of bed height.

Themechanism 200 is selectively operable, utilizingselector lever 106. It is effective to provide inclination of theentire bed 10, includingstationary frame 12,movable frame 14 andmattress supporting frame 16 in either a head end down (Trendelenburg) or a foot end down (reverse Trendelenburg) position.

TheTrendelenburg mechanism 200, best seen in FIGS. 3 and 9 through 11, includes aTrendelenburg hook member 202 pivotally supported upon thestationary frame 12 and a pair ofhook receptacles 204 and 206 associated, respectively, with the headend leg cables 41 and footend leg cables 43.

Thehook member 202 is supported upon thestationary frame 12 in surrounding relation to drivescrew 36 of the high-low operating mechanism by abracket 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 theU-shaped bracket 212 in general vertical alignment, one abovedrive screw 36 and one below.

Similarly, and as best seen in FIG. 2, thehook 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 'ofdrive screw 36. Each leg of the hook member is provided with a pair ofelongated slots 216 which receive cross pins 201. This provides for pivotal support of themember 201 on thebracket 212. The separate legs of the hook member are joined by twocross webs 214, one at the top of the member and one at one end, abovedrive screw 36.

Threenotches 203 are provided across the top of the member for purposes as will be explained.

Each leg of thehook member 202 defines aTrendelenburgclaw 208 and areverse Trendelenburg claw 210. Thus. two claws are defined for each position, one on either side ofdrive screw 36. TheTrendelenburg hook member 202 is spring biased by a apir ofsprings 218, one on each side ofbracket 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 theselector lever 106. Movement of thelever 106 is transferred throughtransverse shaft 116 andlongitudinal shaft 118 andoperating linkage 120.

This linkage includes a generallyvertical link 220 and a generallyhorizontal lever arm 221 shown in cross-section in FIGS. 9 through 11. Thelever arm 221 is fixed tolongitudinal shaft 118. It is shaped to pass beneath longitudinal shaft associated with the highlow actuating mechanism and connects tovertical link 220 at its upper end. v,

Movement ofselector lever 106 in one direction causes pivotal movement ofshaft 118 in a direction to create an upward pull onlink 220 throughlever arm 221. This pivotshook member 202 downwardly. Movement ofselector lever 106 in the opposite direction causes pivotal movement oflongitudinal shaft 118 in the opposite direction. This causeslever arm 221 to push downwardly uponlink 220 and pivotsmember 202 upwardly.

1 1 Thecables 41 and 43 associated withtelescoping legs 24 are connected to the operating nut ofdrive screw 36. As can be appreciated, the position of the operating nut along the drive screw determines the bed height.

I That is, as the nut is moved toward the-foot end of the head end of the bed, the effective length ofcables 41 and 43 is increased. The weight of the bed causes it to move downwardly upon thelegs 24 to accommodate the increased cable lengths.

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

Eachhook receptacle 204 and 206 includes a generallyvertical 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.

Thebooks 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 associatedclaws 210 and 212 of thehook member 202.

When the bed is at the maximum height above the floor, thehook receptacles 204 and 206 are positioned between theclaws 208and 210 of themember 202. Movement of theselector lever 106 to either the Trendelenburg or reverse Trendelenburg selector position will cause themember 202 to be pivoted in the appropriate direction and one or the other of the pairs ofclaws 208 or 210 will be disposed within the receptacle defining aperture of the associatedreceptacle 204 or 206. Thereafter, upon operation of the high-low mechanism 100 to lower the bed uponlegs 24 and movement of the drive screw operating nuttoward the head end of the bed and interengaged claw and receptacles will prevent one of the pairs ofcables 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 provideTrendelenburg positioning, theselector lever 106 is positioned to moveclaw 208 into engagement withreceptacle 206 as illustrated in FIG. 10. This prevents extension ofcable 43 associated withfoot end legs 24. Operation of the high-low mechanism is effective only with respect tocables 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 toposition member 202 as illustrated in FIG. 11 withclaw 210 in engagement withreceptacle 204. Upon actuation of the high-low mechanism, onlycables 43 will be extended, lowering the foot end of the bed.

For patient safety, theclaws 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 theselector lever 106 and accidental disengagement of the claw and receptacle, while the bed is in any position of Trendelenburg. v r

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 shaftl which is connedted to the high-low operating control 100 is provided with a dependingweb 229. The web in sized and positioned such that when theshaft 1 10 is pivoted upon actuation of the control the web is moved into coaction with themember 202. When themember 202 is in the neutral, Trendelenburg or reverse Trendelenburg positions, actuation of the high-low control will cause theweb 229 to pass within one of thenotches 203 formed in the hook member and operation is not impaired. However, if the hook member is positioned inany intermediate position, theweb 229 will engage the leg of themember 202 and pivotal movement of theshaft 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 whenclaws 208 and 210 andreceptacles 204 and 206 are .fully latched or unlatched. 1

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 andscope of the present invention. v

7 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 meansoperatively associated with said thigh section and secured to 7 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.

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 inclaim 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 g 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 ll wherein said member is biased to said neutral position.

13. In an electrically operable hospital bed as claimed inclaim 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 open ative 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.

Claims (13)

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.

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