Abstract:
The present invention relates to an apparatus, such as a bed, having a vertically adjustable deck that is selectably raised and lowered in a substantially vertical manner. Two leg frames are pivotally and movably connected to rails supporting the deck through a slot in the bottom of the rails. Support frames having a fixed longitudinal position relative the bed frame rail are connected to a central pivot point of the leg frames, respectively. The support frames each have a cross member supporting a connection lever defining a path. Actuators are pivotally connected to the bed frame and to a movable pivotal connection point along the path. A control arm is provided to determine the location of the actuator end relative the path of the connection lever. Wheel assemblies can be pivotally connected to the second end of the leg frames.

Description:
This United States utility patent application claims priority on and the benefit of provisional application 61/475,523 filed Apr. 14, 2011, the entire contents of which are hereby incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an apparatus, such as a bed, having a vertically adjustable deck that is selectably raised and lowered in a substantially vertical manner under operation of two leg frames pivotally and movably connected to rails supporting the deck. 
     2. Description of the Related Art 
     Typically, height and angle adjustable beds are used by medical institutions, such as hospitals, nursing homes and/or long or short term care facilities. The beds usually include a bed frame and an articulating mechanism for lowering the bed frame to a low position and raising the bed frame to a high position so that it may be used as a gurney or at any height in between. As a result, a patient can be transferred by merely sliding the patient from one gurney to another or a chair. 
     Examples of beds include: 
     United States published application having publication number 2009/0094747 to Bly, and assigned to Invacare Corporation, is titled Bed Lift Mechanism. This publication illustrates a bed with a leg assembly coupled to a support link assembly by a joint, the joint comprising a slot having at least two paths. A support link assembly defining a length that automatically varies as the support link assembly moves relative to the leg assembly. 
     United States patent number (hereafter “U.S. Pat. No.”) 7,334,277 to Johnson, and assigned to Raye&#39;s, Inc. is titled Low Profile Hospital Bed. This patent shows a low profile hospital bed with a mattress support frame and pivotably mounted wheel frames. Lift actuators connecting between the mattress support frame and the wheel frames move the wheel frames between a folded position and an unfolded position. When the wheel frames are in the folded position, the lift actuators are relatively horizontal and thus unable to provide enough vertical force to move the wheel frames. Accordingly, connecting between the actuators and the wheel frames are leverage members which rotate and urge the wheel frames away from mattress support frame during an initial, first stage of movement as the wheel frames partially unfold. After the first stage of movement, the leverage members function as simple mechanical links between the lift actuators and the wheel frames as the lift actuators continue to power the complete unfolding of the wheel frames. 
     U.S. Pat. No. 6,729,667 to Henderson et al., and assigned to Howard Wright Limited, is titled Stretcher Suspension Linkages. It illustrates a linkage that includes a stretcher receiving frame and a base frame. A pair of arms are pivotally fixed to bottom frame and slidingly connected to frame. A pneumatic suspension unit is located between the arms and a first link pivotally coupled between arms and frame. A cross member of the slide coupling is coupled to a sliding mount of a second link pivotally coupled to an arm pivotally connected to the frame and sliding coupled to the base frame. 
     U.S. Pat. No. 6,473,922 to Sommerfeld et al., and assigned to Sunrise Medical HHG, Inc., is titled Kinematic Motion of Articulated Bed. This patent shows an articulated bed with a main frame supported by a leg tube. An upper portion of the leg tube is longitudinally and pivotally displaceable relative to the main frame at an upper movable pivot point. A lower portion of a stabilizer is connected to a lower intermediate portion of the leg tube at a lower orbital pivot point. An upper portion of the stabilizer is pivotally connected relative to said main frame at an upper fixed pivot point. A wheel is pivotally attached to a lower portion of the leg tube at a pivot axis. The upper movable pivot point, the lower orbital pivot point, and the pivot axis do not coalign and the distance between the upper fixed pivot point and the upper movable pivot point are maximized when the main frame is in a raised position. The bed of this invention is illustrated schematically in  FIG. 10  where it is seen that a pivot axis D, pivot point C and pivot point B do not coalign. 
     U.S. Pat. No. 5,432,966 to Berta et al. is titled Adjustable Ambulance Cot with Trolley Mechanism. It shows an adjustable roll-in ambulance cot having a cot frame having a leading end, a trailing end, and a pair of opposing side frame members. The cot is supported by leading and trailing pairs of collapsible legs having respective upper ends connected to the cot frame and lower ends including transport wheels thereon for transport of the cot. Mechanisms are also provided for adjusting the height of the cot frame relative to the transport wheels and for latching the cot frame into a plurality of predetermined positions for patient transfer and loading. 
     U.S. Pat. No. 4,718,355 to Houghton is titled Vertically Adjustable Patient Support Table. It illustrates a patient support platform with a compound leg structure which allows the platform to move to a squatted position giving easy access for a patient or to disposition of a patient thereon and, at the same time, the platform is adjustable to elevated positions so that a standing attendant may administer to the patient. Supporting feet are disposed in a fixed, predetermined pattern and provide pivot points to which the compound leg structures are pivoted. The compound leg structures effect raising and lowering of the platform without changing or disturbing the positions of the feet. 
     U.S. Pat. No. 2,675,285 to Terry et al. is titled Vertically Adjustable Therapy Treatment Table having Hinged End Sections. It shows a table with folding legs. The legs are connected to and actuated by sleeves slidaby mounted on a threaded rod extended longitudinally through a supporting frame and rotated by a crank. 
     None of these references show a bed with structures adapted to level the loading output of the actuators by having a connection lever defining a path that is offset from a support frame cross member, wherein the position of the actuator end relative the connection lever path is controlled by a control arm. 
     None of these references shown a bed with outwardly angled leg frames with their pivots slidable along the bed frame, with a set of supports having a fixed longitudinal position extending from the bed frame to a central pivot point of the leg frames, and actuators are connected to the bed frame and to a movable pivotal connection point offset from the cross member. 
     None of these references show a bed with movably and pivotably connected legs, wherein the movable and pivotable connection is between the legs and a frame having a slotted bottom member (or tube) to provide symmetry at the connection, maintain structural integrity of the member and eliminate pinch points. 
     Thus there exists a need for an apparatus such as a bed that solves these and other problems. 
     SUMMARY OF THE INVENTION 
     The present invention relates to an apparatus, such as a bed, having a vertically adjustable deck that is selectably raised and lowered in a substantially vertical manner. Two leg frames are pivotally and movably connected to rails supporting the deck through a slot in the bottom of the rails. Support frames having a fixed longitudinal position relative the bed frame rail are connected to a central pivot point of the leg frames, respectively. The support frames each have a cross member supporting a connection lever defining a path. Actuators are pivotally connected to the bed frame and to a movable pivotal connection point along the path. A control arm is provided to determine the location of the actuator end relative the path of the connection lever. Wheel assemblies can be pivotally connected to the second end of the leg frames. 
     According to one advantage of the present invention, the bed can have structures adapted to level the loading output of the actuators. This is accomplished in one embodiment by having a connection lever defining a path that is offset from a support frame cross brace. A control arm then can control the position of the actuator end relative the connection lever path. 
     According to another advantage of the present invention, the bed has outwardly angled leg frames with their pivots slidable, rollable or otherwise movable along or within the bed frame and a set of supports having a fixed longitudinal positions extend from the bed frame to a central point of the respective leg frames. This allows the bed to raise and lower in a substantially vertical manner. 
     According to a still further advantage of the present invention, the rails have bottom surfaces that are slotted along the middle portion, wherein the movably and pivotably connected leg frames are received within slotted structure to eliminate pinch points. 
     In one preferred embodiment, a translation assembly is provided for moving within the frame member. Advantageously, the translation assembly can be configured in one embodiment to slide in one direction and roll in the opposed direction within the frame member. 
     Other advantages, benefits, and features of the present invention will become apparent to those skilled in the art upon reading the detailed description of the invention and studying the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a preferred embodiment of the present invention in a high position. 
         FIG. 2  is an additional perspective view of the preferred embodiment illustrated in  FIG. 1 . 
         FIG. 3  is a close up perspective view showing an embodiment of the actuator received within the path. 
         FIG. 4  is a side view of the preferred embodiment of the present invention shown in  FIG. 1  in a high position. 
         FIG. 5  is a side view of the preferred embodiment of the present invention shown in  FIG. 1  in a mid position. 
         FIG. 6  is a side view of the preferred embodiment of the present invention shown in  FIG. 1  in a low position. 
         FIG. 7  is schematic view of the preferred embodiment of the present invention shown in  FIG. 1  in a high position. 
         FIG. 8  is schematic view of the preferred embodiment of the present invention shown in  FIG. 1  in a mid position. 
         FIG. 9  is schematic view of the preferred embodiment of the present invention shown in  FIG. 1  in a low position. 
         FIG. 10  is a cross-sectional view taken through a pivotal connection of the translation assembly where the leg frame is pivotally and movably connected to a rail. 
         FIG. 11  is a perspective isolation view of a preferred translation assembly. 
         FIG. 12  is a lower perspective view of a preferred embodiment of the present invention. 
         FIG. 13  is a schematic view of an alternative preferred embodiment showing a roll in low only configuration in the high position. 
         FIG. 14  is a schematic view of an alternative preferred embodiment shown in  FIG. 13  in the low position. 
         FIG. 15  is a schematic view of an alternative preferred embodiment shown in  FIG. 13  in the roll position. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     While the invention will be described in connection with one or more preferred embodiments, it will be understood that it is not intended to limit the invention to those embodiments. On the contrary, it is intended to cover all alternatives, modifications and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims. 
     A first preferred embodiment of the present invention is illustrated in  FIGS. 1-12 . Specifically looking at  FIGS. 1-6  and  12 , it is seen that a bed  5  having a deck  10  supported by rails  20  and  30 , leg frame  50 , wheel assemblies  60  and  70 , support frame  80 , actuator  90 , control arm  100 , leg frame  150 , wheel assemblies  160  and  170 , support frame  180 , actuator  190  and control arm  200  are provided. Each of these components is described in detail below. Specifically looking at  FIGS. 7-9 , it is seen that the motions of the components are shown schematically. 
     The deck  10 , rail  20  and rail  30  can be collectively called the bed frame  7 . The deck  10  of the bed  5  has a first end  11  and a second end  12 . A first rail  20  is on the first side of the deck spanning preferably nearly entirely between the ends  11  and  12 , and a second rail  30  is provided on the opposite side. Rail  20  has a first slot  21  and a first fixed hole  22 , and a second slot  23  and a second fixed hole  24 . Slot  21  and hole  22  are on one end of the rail, and slot  23  and hole  24  are on the opposite end of the rail. Slot  21  and slot  23  are preferably located on the underside of rail  20  preferably equidistant between sides of the rail. Yet, it is appreciated that other configurations can be provided without departing from the broad aspects of the present invention. Rail  30  is preferably identical to rail  20 . 
     It is appreciated that while generally rectangular profile rails  20  and  30  are illustrated, that other profile shapes can be used without departing from the broad aspects of the present invention. The slots are preferably located on the bottom of the rails so that the vertical components thereof remain intact to retain maximum structural integrity. 
     Leg frame  50  has ends  51  and  52  with an intermediate point  53  preferably generally equidistant between the ends. The leg frame  50  has two side members  54  and  55  and a leg cross bar  56  at or near the bottom or distal end  52  spanning between the two side members. The first or connecting end  51  of the leg frame  50  is received within slot  21  of rail  20  and within the first end slot within rail  30 . It is appreciated that a rigidly connected ear or lug having a narrow profile is provided at the end of the leg frame  50  so that it can pass through slot  21 . The first end  51  can have a retainer such as a translation assembly  75  that maintains the connection between the end  51  and the rails to allow the end  51  to be pivotally and movably retained within the rail. 
     Wheel assembly  60  has a frame  61  and wheels  62 . The wheel frame  61  is preferably pivotally connected to end  51  of the leg frame  50  on side  54 . Wheel assembly  70  has a frame and wheels. The wheel frame is preferably pivotally connected to end  51  of the leg frame  50  on side  55 . The wheel assemblies  60  and  70  are pivotally connected to the leg frame along a wheel assembly pivot axis. 
     As best seen in  FIGS. 10 and 11 , the translation assemblies  75  have a pivot axis  76  and opposed ends  77  and  78 . The first end  77  can be adapted to slide and the second end can be mated with a roller or wheel  79  to provide rolling friction instead of sliding friction. Each translation assembly is preferably substantially or completely housed within the respective rail. Sliding friction can be the prevailing friction force when the translation assembly is moving in a first direction, and rolling friction can be the prevailing friction when the translation assembly is moving in the opposite or second direction. In is understood that the illustrated embodiment of the translation assembly is exemplary in nature, and the translation mechanism could have other structures, even a single block without departing from the broad aspects of the present invention. 
     A support frame  80  is further provided, and has a first end  81  and a second end  82 . Support frame  80  has two sides  83  and  84 , and one or more cross members  85 . A connection lever  86  is connected to a cross member  85 . It is understood that the connection lever  86  could be attached to more than one cross member without departing from the broad aspects of the present invention. The connection lever defines a path  87  (or slot, channel or other structure). The path can accommodate a roller or other type of device to facilitate movement along the path. Path  87  is preferably arcuate, but may be straight without departing from the broad aspects of the present invention. End  81  of support frame  80  is preferably pivotally connected to rail  20  at hole  22  and also to rail  30 . End  82  is preferably pivotally connected to intermediate point  53  of the leg frame  50  about the support frame and leg frame pivot axis. The length of the support frame  80  is equal to ½ of the length of the leg. The support frame preferably dissects the length of the leg frame  50  to two equal lengths on each side of the intermediate point  53 . Any given fixed point on path  87  of the connection lever  86  orbits about the support frame and pivot frame pivot axis. It is understood that the geometric longitudinal shape of path  87  can vary as desired to impart any desired path relative the support frame and pivot frame pivot axis. 
     Actuator  90  has opposed ends  91  and  92 . Actuator  90  is preferably a linear actuator. Actuator end  91  is preferably pivotally connected to deck  10 , and end  92  is preferably movably and pivotally connected to the connection lever  86  at a point along path  87 . 
     Control arm  100  has ends  101  and  102 . End  101  of control arm is pivotally connected to the deck  10 , and end  102  is connected to the second end  92  of the actuator  90  to control the location of the actuator end  92  within path  87 . In the illustrated embodiment, the angle between control arm  100  and the actuator  90  is acute when the bed  5  is in a high position, and obtuse when the bed  5  is in the low position. The control arm  100  is in tension when the angle is acute, and is in compression when the angle is obtuse. The control arm is neither in compression nor tension when the angle is a right angle. It is understood that the angle between the control arm and actuator may remain obtuse throughout the entire stroke of the actuator without departing from the broad aspects of the present invention. 
     The wheel frame pivot axis is preferably aligned with the leg frame and rail pivot axis and the leg frame and support frame pivot axis along a straight line, as seen in the schematic drawings of  FIGS. 7-9 . 
     It is preferred that the pivot axis between the leg frame  50  and the rail  20 , and the pivot axis between the support frame  80  and the rail are generally horizontal. Yet, it is understood that the leg frame pivot axis could be marginally higher than the support frame pivot axis under zero-load conditions so that they may become horizontally aligned under the frame deflections that will occur under maximum anticipated loading conditions. 
     Leg frame  150  is similar to frame  50  and has ends with an intermediate point preferably equidistant between the ends. The leg frame  150  has two side members and a leg cross bar at or near the bottom or distal end spanning between the two side members. 
     The first or connecting ends of the leg frame  150  sides are received within slot  23  of rail  20  and within the first end slot within rail  30 , respectively. It is appreciated that a rigidly connected ear or lug having a narrow profile is provided at the end of the leg frame  150  so that it can pass through slot  23 . The first end can have a translation assembly  75  that maintains the connection between the leg frame and the rails in a symmetric relationship, and also allows the end of the leg frame to be pivotally and movably retained by the rails. It is appreciated that while rails are shown, that other connectors may be utilized without departing from the broad aspects of the present invention. 
     Wheel assembly  160  has a frame and wheels. The wheel frame is preferably pivotally connected to the end of the leg frame on the first side of the frame. Wheel assembly  170  has a frame and wheels. The wheel frame is preferably pivotally connected to end of the leg frame  150  on side the leg frame second side. The wheel assemblies  160  and  170  are pivotally connected to the leg frame along a wheel assembly pivot axis. 
     A support frame  180  is further provided, and has a first end and a second end. Support frame  180  has two sides and a cross member. A connection lever is connected to the cross member. The connection lever defines a path (or slot, channel or other structure). The path is preferably arcuate, but may be straight without departing from the broad aspects of the present invention. The ends of support frame  180  are preferably pivotally (but longitudinally stationarily) connected to rail  20  at hole  24  and also to rail  30 . The opposite end of the frame  180  is preferably pivotally connected to intermediate point of the leg frame  150  about the support frame and leg frame pivot axis. The length of the support frame  180  is equal to ½ of the length of the leg. The support frame preferably dissects the length of the leg frame  150  to two equal lengths. Any given fixed point on the path of the connection lever orbits about the support frame and pivot frame pivot axis. It is understood that the geometric longitudinal shape of path can vary as desired to impart any desired path relative the support frame and pivot frame pivot axis. 
     Actuator  190  is provided and has opposed ends. Actuator  190  is preferably a linear actuator. The actuator first end is preferably pivotally connected to deck  10 , and the second is preferably movably and pivotally connected to the connection lever at a point along its path. 
     Control arm  200  is further provided. The first end of control arm is pivotally connected to the deck  10 , and the second end is connected to the second end of the actuator  190  to control the location of the actuator end within the path of the connection lever. The angle between control arm  200  and the actuator  190  is acute when the bed  5  is in a high position, and obtuse when the bed  5  is in the low position. The control arm  200  is in tension when the angle is acute, and is in compression when the angle is obtuse. The control arm is neither in compression nor tension when the angle is a right angle. It is appreciated that leg frames  50  and  150  work in equal and opposite manners to achieve a substantially vertical rise in the bed  5 . However, it is further appreciated that in an alternative embodiment of the present invention (not shown), that a drag link or similar structure could be provided so that one of the two actuators could be eliminated. 
     Turning now to  FIGS. 13-15 , an alternative embodiment is shown schematically. The bed  305  is a roll in low only design, having a deck  310  with a rail  320 , a leg frame  350 , a support frame  180  and an actuator  390 . A low only wheel assembly  400  with a wheel  401  is also shown. On the opposite side of the bed  305  are a second leg frame  450 , wheel assembly  460 , support frame  480  and actuator  490 . A second low only wheel assembly  500  with wheel  501  is further provided. The wheels  401  and  501  are only operational when the bed  305  is all the way in the lowest position, when wheel assemblies  360  and  460  are rotated off of the ground. 
     Thus it is apparent that there has been provided, in accordance with the invention, a height adjustable apparatus that fully satisfies the objects, aims and advantages as set forth above. While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications, and variations as fall within the spirit and broad scope of the appended claims.