Patent Publication Number: US-7712168-B2

Title: Articulating bed and method of using the same

Description:
BACKGROUND 
   1. Field 
   The present disclosure relates to a bed, and more particularly, pertains to an articulating bed. 
   2. Discussion of Related Technology 
   A typical bed includes a frame and a mattress placed over the mattress. Some beds have two or more sections that are bendable relative to each other. Some of these bendable beds are powered by electric motors and change between the flat (lying) configuration and the bent (sitting) configuration. These powered bending beds are typically used in hospitals and nursing homes. 
   SUMMARY 
   One aspect of the invention provides a bed, which comprises: a first frame comprising a first side section and a second side section; a second frame supporting the first frame; and wherein a first side section is configured to slide in a lateral direction of the bed so as to vary a width of the bed. 
   In the foregoing bed, the first side section and the second side section may be coupled together and configured to slide together. In a first configuration of the bed, the first frame may substantially eclipse the second frame when viewed from the top, and the bed has a first width, and wherein in a second configuration of the bed, a substantial portion of the second frame may be exposed when viewed from the top, and the bed has a second width, which is larger than the first width. In the first configuration, the first and second sections may define a mattress support area over which a mattress is to be supported, and wherein in the second configuration, the exposed portion of the second frame and the first and second sections may together define the mattress support area over which a mattress is to be supported. 
   Still in the foregoing bed, the second side section may be configured to remain still or slide in the lateral direction independent of the first side section. The first and second side sections may be configured to slide relative to each other between a first relative position and a second relative position, wherein in the first relative position, the first and second side sections may be located the closest with each other, wherein in the second relative position the first and second side sections may be the most remotely located from each other, and wherein in the second relative position. a mattress support area may be larger than in the first relative position. The second frame may comprise a slider and a sliding guide, wherein the slider may be slidably engaged with the sliding guide and may be configured to slide generally in the lateral direction, wherein the slider may be attached to the first side section such that sliding of the first side section is guided by the sliding guide of the second frame. The bed may further comprise a hinge having a hinge axis and hingedly interconnecting the first side section and the slider, wherein the first side section may be configured to hingedly rotate about the hinge axis. The bed may further comprise a sliding mechanism configured to power sliding of the first section. 
   Further in the foregoing bed, the first side section may comprise a first side rail generally extending in a longitudinal direction of the bed, wherein the first side section may be further configured to hingedly rotate about a first axis generally parallel to the longitudinal direction such that the first side rail is lifted. The bed may further comprise a hinge hingedly connecting between the first side section and the second frame, wherein the first side section may be configured to hingedly rotate via the hinge. The bed may further comprise a lifting mechanism configured to power hinged rotation of the first section. 
   The bed may further comprise an actuating device configured to power both sliding and hinged rotation of the first section. The actuating device may comprise a driving rod, a first traveling nut and a second traveling nut, wherein the driving rod may extend generally in the lateral direction and configured to rotate, wherein the first and second traveling nuts may be engaged with the driving rod and configured to travel along the driving rod as the driving rod rotates. The first traveling nut may be connected to the first side section and configured to power sliding of the first side section in the lateral direction while traveling along the driving rod. The driving rod may comprise a threaded portion and two non-threaded portion at both ends of the threaded portion, wherein the first and second traveling nuts may be configured to travel along the driving rod while engaged with the threaded portion, wherein the first and second traveling nuts may be configured to stop traveling when reaching the non-threaded portion. The first traveling nut may be configured to power hinged rotation of the first side section while traveling along the driving rod if the second traveling nut reaches the non-threaded portion. 
   Another aspect of the invention provides a bed, which comprises: a first frame; a second frame underlying the first frame, wherein the first frame is configured to slide relative to the second frame between a first position and a second position; and a sliding mechanism configured to power sliding of the first frame between the first position and the second position, wherein in the first position, the first frame substantially eclipses the second frame when viewed from the top, and wherein in the second position, a substantial portion of the second frame is exposed when viewed from the top. 
   Still another aspect of the invention provides a bed, which comprises: a first frame comprising a first section and a second section, the first section comprising a first side rail, the second section comprising a second side rail, wherein the first side rail is arranged to be generally linear with the second side rail; and a lifting bar comprising a first lifting segment and a second lifting segment hingedly connected with the first lifting segment, wherein the first lifting segment and second lifting segment are configured to hingedly rotate relative to each other about a first axis such that the first section and the second section hingedly rotate relative to each other about the first axis, wherein the first lifting segment is engaged with the first side rail, wherein the second lifting segment is engaged with the second side rail, wherein the first lifting segment and the second lifting segment are in combination configured to hingedly rotate the first side rail and the second side rail about a second axis substantially perpendicular to the first axis. 
   A further aspect of the invention provides a method of operating a bed, which comprises: providing a bed comprising a first frame and a second frame underlying the first frame, wherein the bed comprising a mattress support area configured to support a mattress, wherein the mattress support area has a width, which is a distance between two ends of the bed in a lateral direction; and sliding the first frame relative to the second frame in a lateral direction of the bed so as to vary the width. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a bird-eye view of an articulating bed according to an embodiment of the invention; 
       FIG. 2  is an exploded view of the bed in  FIG. 1 , illustrating a top frame, an intermediate frame, and a base frame; 
       FIG. 3A  is an exploded view of the top frame; 
       FIG. 3B  illustrates the engagement of components of the top frame in  FIG. 3A ; 
       FIG. 4A  illustrates the engagement between the top frame and the intermediate frame; 
       FIG. 4B  further illustrates the engagement between the top frame and the intermediate frame; 
       FIG. 4C  illustrates the engagement between a slidable hinge support bar and a roller guide bar of the intermediate frame; 
       FIG. 4D  illustrates sliding rollers between the top and intermediate frames; 
       FIG. 4E  is a bottom view of the top frame showing the sliding rollers in  FIG. 4D ; 
       FIG. 5  illustrates a configuration of the bed, in which the top frame that has been slid to one side; 
       FIG. 6A  illustrates a configuration of the bed, in which a left section of the top frame that has been lifted; 
       FIG. 6B  illustrates a configuration of the bed, in which a right section of the top frame that has been lifted; 
       FIG. 7A  illustrates a sliding and lifting mechanism of the bed; 
       FIG. 7B  illustrates a connection between the top frame and the sliding and lifting mechanism; 
       FIGS. 8A and 8B  illustrate sliding operation with the sliding and lifting mechanism; 
       FIGS. 9A and 9B  illustrate lifting of a left or right section of the top frame and the operation of the sliding and lifting mechanism for the lifting; 
       FIGS. 10A ,  10 B, and  10 C illustrate sliding and lifting operations of the bed from another perspective; 
       FIG. 11  illustrates a sitting configuration of the bed; 
       FIG. 12  illustrates hinged interconnections between the top, intermediate and base frames; 
       FIG. 13  illustrates a mattress assembly according to an embodiment of the invention; 
       FIG. 14A  illustrates a configuration of the mattress assembly placed over the bed, in which the top frame is in the center position; 
       FIG. 14B  illustrates a configuration of the mattress assembly placed over the bed, in which the top frame has been slid to one side; 
       FIG. 14C  illustrates a configuration of the mattress assembly placed over the bed, in which the left section of the top frame has been lifted; 
       FIGS. 15A and 15B  illustrate a head rest according to an embodiment; 
       FIGS. 16A and 16B  illustrate the engagement of the head rest with the bed; 
       FIGS. 17A and 17B  illustrate operation for sitting up a person lying on the bed to face to the side; 
       FIG. 18  is a flowchart for the sitting-up-to-side operation illustrated in  FIGS. 17A and 17B . 
       FIGS. 19A and 19B  illustrate the operation for changing a liner of the bed while a person is lying on the bed; and 
       FIG. 20  is a flowchart for the liner-changing operation. 
   

   DETAILED DESCRIPTION OF EMBODIMENTS 
   Various features and advantages of the invention will be described in terms of embodiments and examples with reference to the foregoing drawings. Those having ordinary skill in the art may be able to make alterations and modifications what is described herein without departing from its spirit and scope. Therefore, it must be understood that what is illustrated and described herein is set forth only for the purposes of example and that it should not be taken as a limitation. 
   Referring to  FIGS. 1 , and  2 , an articulating bed  1000  according to an embodiment includes a top frame  100 , an intermediate frame  200 , and a base frame  300 . The top frame  100  is placed over the intermediate frame  200 , which is placed over the base frame  300 . In other embodiments, the bed  1000  may include one or more additional frames (not illustrated). Further, in other embodiments, it is not necessary that the articulating bed include all of the top, intermediate and base frames  100 ,  200 ,  300 . The bed  1000  can be constructed in any sizes including twin, full, long twin, queen, king and California king beds. 
   The bed  1000  optionally includes a head board  316  and a foot board  318 . The bed  1000  further includes a head section  362 , a hip section  364 , an upper leg section  366  and a lower leg section  368 . Each of these sections  362 ,  364 ,  366  and  368  refer to collectively a portion of the top frame  100  and a portion of the intermediate frame  200 , although it could include a portion of base frame  300  in certain other embodiments. As shown in  FIG. 1 , the longitudinal directions of the bed are the direction along the head section  363 , hip section  364 , upper leg section  366  and lower leg section  368 . The lateral directions of the bed are perpendicular to the longitudinal directions. The distance between the two ends of the bed in the longitudinal direction is defined as the “length” of the bed. The distance between the two ends of the bed in the lateral direction is defined as the “width” of the bed. 
   In the illustrated embodiment, the articulating bed  1000  is configured to allow the top frame  100  or its portion(s) to slide sideways (in the lateral direction) over the intermediate frame  200 . Further, a portion of the top frame  100  is configured to be lifted. Moreover, the head, hip, upper leg and lower leg sections  362 ,  364 ,  366 ,  368  are configured to bend with respect to the others. These sliding, lifting and bending features of the bed  1000  will be described in more detail. 
   In this disclosure, the terms “right” and “left” refer to the right and left sides of a person lying on the bed with the head over the head section  362  and the legs over the leg sections  366 ,  368  of  FIG. 1 . Thus, these terms “right” and “left” do not necessarily refer to certain illustrated features that are located on the right-hand or left-hand side of the drawing sheets. 
   Top Frame 
   The top frame  100  includes a head section  162 , a hip section  164 , an upper leg section  166 , and a lower leg section  168 , which correspond to the head section  362 , hip section  364 , upper leg section  366  and lower leg section  368 , respectively. The top frame  100  includes left side rails  162 A,  164 A,  166 A,  168 A, right side rails  162 B,  164 B,  166 B,  168 B, head rails  152  and foot rails  154 , which in combination generally define the lying area of the bed  1000 . The top frame  100  further includes a plurality of mattress support bars  110 ,  106 ,  116 ,  118  that are to support a mattress to be placed over them. 
   Each of the head section  162 , upper leg section  166  and lower leg section  168  is formed by some of the mattress support bars  110 , the left side rails  162 A,  166 A,  168 A, and the right side rails  162 B,  166 B,  168 B. The mattress support bars  110  of the head, upper leg and lower leg sections  162 ,  166 ,  168  are generally in the same shape, though not necessary. Some of the mattress support bars  110  are fixed to the right side rails  162 B,  166 B,  168 B, and the others are fixed to the left side rails  162 A,  166 A,  168 A. As illustrated, for example, the mattress support bars  110  are attached to the left and right side rails  162 A,  166 A,  168 A,  162 B,  166 B,  168 B staggeringly. 
   As will be discussed later, the hip section  364 ,  164  of the bed  1000  is used in actuating the sliding and lifting operations of the bed  1000 . For this reason, the left side rail  164 A and the right side rail  164 B of the hip section  164  are slightly differently shaped from the other left and right side rails  162 A,  166 A,  168 A,  162 B,  166 B,  168 B. The hip section  164  includes mattress support bars  106 ,  116 ,  118 , which are slightly differently shaped and arranged from the other mattress support bars  110 ; however, these differences may not be necessary. 
   In other embodiments, one or more of the other sections  362 ,  366 ,  368  in addition to the hip section  364  can be used in actuation of the sliding and lifting operations, and the shapes and arrangements of their components can be configured accordingly. Also, in other embodiments, one or more of the other sections  362 ,  366 ,  368  can be used in the actuation of the sliding and lifting operations in replacement of the hip section  364 , and the shapes and arrangements of their components can be configured accordingly. 
   In the illustrated embodiment, several straps  132 ,  134  are formed crossing the mattress support bars  110  of the head, upper leg and lower leg sections  162 ,  166 ,  168 . Each strap  132 ,  134  combines two or more mattress support bars  110 , which are attached to the same side rail and further belonging to a single section  162 ,  166  or  168 . These mattress support bars  110  combined by a strap  132 ,  134  are to move together in the sliding, lifting and being operations. Although not illustrated, if needed, one or more straps may be formed on the mattress support bars  106 ,  116  to combine them. The straps  132 ,  134  can be replaced with other appropriate means or forms of combining two or more mattress support bars. In some embodiments, some of the mattress support bars  106 ,  110 ,  116 ,  118  are replaced with a board or plate for supporting mattress, in which combining straps may not be needed. 
   Intermediate Frame 
   The intermediate frame  200  includes a head section  262 , a hip section  264 , an upper leg section  266 , and a lower leg section  268 , which respectively correspond to the head section  362 , hip section  364 , upper leg section  366  and lower leg section  368  of the articulating bed  1000 . The intermediate frame  200  is composed of left side bars  262 A,  264 A,  266 A,  268 A, right side bars,  262 B,  264 B,  266 B,  268 B, and roller guide bars  214  interconnecting the left and right side bars. In the illustrated embodiment, each section  262 ,  264 ,  266 ,  268  of the intermediate frame  200  is generally defined by two opposing side bars and two opposing roller guide bars. 
   Further, each section  262 ,  264 ,  266 ,  268  includes two slidable hinge support bars  220 , which are arranged substantially parallel, although not limited thereto. The opposing ends of each slidable hinge support bar  220  are slidably engaged with two opposing roller guide bars  214  of each section  262 ,  264 ,  266 ,  268 , which will be discussed later in detail. In some embodiment, the slidable hinge support bars  220  of each intermediate frame section are interconnected with the slidable hinge support bars  220  of neighboring intermediate sections, although not limited thereto. The interconnection between the slidable hinge support bars  220  of the neighboring intermediate sections facilitates sliding operation of the top frame, which will be discussed later. 
   Base Frame 
   The base frame  300  supports the top and intermediate frames  100 ,  200 . The base frame  300  includes two substantially parallel side bars  310  and two substantially parallel head/foot bars  312 . In the illustrated embodiment, although not necessary, the base frame  300  is supported by four legs  314  with wheels  320 , and a head board  316  and foot board  318  are connected to the base frame  300  so as to provide a basic configuration of a bed. Further, the base frame  300  anchors the sliding and lifting mechanism  340 , which will be further discussed in detail. 
   Connections Among the Top Frame Sections 
     FIGS. 3A and 3B  illustrate an embodiment of connections among the top frame sections. In the illustrated embodiment, extensions  182 A,  186 A,  188 A,  182 B,  186 B,  188 B are connected to the left and right side rails  164 A,  164 B of the hip section  164  of the top frame  100 . The extension  182 A is hingedly connected to the left side rail  164 A of the hip section  164  at a joint  172 . The extension  186 A is hingedly connected to the left side rail  164 A at a joint  174 . Similarly, the extensions  182 B,  186 B are hingedly connected to the left side rail  164 B of the hip section  164 . The extension  188 A is hingedly connected to the extension  186 A at a joint  176 , and the extension  188 B is also hingedly connected to the extension  186 B. These hinged connections allows each extension  182 A,  186 A,  188 A,  182 B,  186 B,  188 B to bend relative to its neighboring extension and accordingly allows each section  162 ,  164 ,  166 ,  168  to bend relative to its neighboring section. 
   Each of the left and right side rails  162 A,  166 A,  168 A,  162 B,  166 B,  168 B has a generally L-shaped cross-section, although not limited thereto. The L-shaped cross-section of the side rails facilitate that the extensions  182 A,  186 A,  188 A,  182 B,  186 B,  188 B are received by and engaged with these side rails from the underside. More specifically, the extension  182 A is received by the left side rail  162 A, the extension  186 A is received by the left side rail  166 A, and the extension  188 A is received by the left side rail  168 A. Likewise, the extensions  182 B,  186 B,  188 B are received by the right side rails  162 B,  166 B,  168 B, respectively. 
   Hinged Connection Between Top and Intermediate Frames 
     FIG. 4A  illustrates an embodiment of the connection between the upper leg section  166  of the top frame  100  and the upper leg section  266  of the intermediate frame  200 , and further illustrates an embodiment of the connection between the lower leg section  168  of the top frame  100  and the lower leg section  268  of the intermediate frame  200 .  FIG. 4B  illustrates an embodiment of the connection between the hip section  164  of the top frame  100  and the hip section  264  of the intermediate frame  200 . Each of the top frame sections is connected to the corresponding section of the intermediate frame  200  via the slidable hinge support bars  220 . 
   Hinges  120  are formed on each of the slidable hinge support bars  220 , facing the top frame  100 . Each hinge  120  is interposed between the slidable hinge support bar  220  and one of the mattress support bars  110 ,  106 ,  116 ,  118  and forms a hinged connection therebetween. With the hinged connection, each mattress support bar is rotatable about the axis of the hinge, as will be discussed further. 
   Slidable Connection Between Top and Intermediate Frames 
   In embodiments, the slidable hinge support bars  220  are slidably engaged with the roller guide bar  214 . Since the intermediate frame  200  are connected to top frame  100  via the above-discussed hinged connection, as the slidable hinge support bars  220  slide relative to the roller guide bars  214 , the top frame  100  and the intermediate frame  200  are to slide relative to each other. 
   Referring to  FIGS. 4A and 4B , two opposing ends of each slidable hinge support bar  220  are engaged with two roller guide bars  214 . In the illustrated embodiments, each end of the slidable hinge support bar  220  has horizontal and vertical rollers  222 ,  224 , which connect with the roller guide bar  214 . The horizontal roller  222  is supported by a horizontal roller support  223 , which is attached to the slidable hinge support bar  220  near its end facing the roller guide bar  214 . The vertical roller  224  is directly connected to the end of the slidable hinge support bar  220 . On the other hand, the roller guide bar  214  has a guide channel in its hollow body. 
   Both the horizontal and vertical rollers  222 ,  224  are received and kept in the guide channel, contacting the interior surfaces of the guide channel and movable along the guide channel. With these engagement, as the slidable hinge support bar  220  slides to the left or right, the horizontal and vertical rollers  222 ,  224  rotates within the guide channel of the roller guide bar  214  and facilitate the sliding operation of the slidable hinge support bar  220 . 
   In other embodiments, one or more additional rollers can be provided to facilitate the slidable engagement between the roller guide bar  214  and the slidable hinge support bars  220 . In other embodiments, the orientation of the rollers can differ from what is illustrated. Further, in other embodiments, the shape of the rollers and the interior surface of the guide channel can differ from what is illustrated. In other embodiments, the roller guide bar  214 , despite its name, can be slidably engaged with the slidable hinge support bars  220  without a roller via other forms of slidable engagement, such as lubrication and using bearing. Further, in other embodiments, these other forms of slidable engagement can be used in addition to at least one of the horizontal and vertical rollers  222 ,  224 . 
     FIGS. 4D and 4E  provide an embodiment that can further facilitate the sliding between the top and intermediate frames  100 ,  200 . In the illustrated embodiment, each strap  132  has rollers  142  on its surface facing the intermediate frame  200 . The rollers  142  contact the top surface of the roller guide bars  214 . These rollers  142  are arranged to roll along the top surface of the roller guide  214  as the top frame  100  slides relative to the intermediate frame  200  as will be discussed now. The rollers  142  are optional in various embodiments of the bed. Further, in other embodiments, additional rollers can be provided to facilitate the sliding between the top and intermediate frames  100 ,  200 . Further, in other embodiments, additional or alternative means and tools can be provided for facilitating the sliding between the top and intermediate frames  100 ,  200 . 
   Sliding of Top Frame 
     FIG. 5  illustrates a configuration of the bed  1000  according to an embodiment. In the illustrated configuration, the top frame  100  has been slid to the left side thereof (right side of the drawing sheet). The sliding of the top frame  100  exposes a portion  280  of the intermediate frame  200 , which is under the top frame  100  when the top frame  100  is in its normal position as illustrated in  FIG. 1 . Optionally, the intermediate frame  200  has a mesh structure  230  in the exposed portion  280  in order to support a person&#39;s body or anything that can be placed on that portion at the time when the bed is in the configuration shown in  FIG. 5 . Although not illustrated, the top frame  100  is capable of sliding to the other side and expose another portion of the intermediate frame  200 . Optionally, a mesh structure is formed in the other portion as well. 
   Lifting of Top Frame 
     FIG. 6  illustrates a configuration of the bed  1000  according to an embodiment. In the illustrated configuration, the top frame  100  has been slid to the left side thereof and further a left section  192 A of the top frame  100  is raised. Here, the term “left section”  192 A refers to collectively the left portions of the head section  162 , hip section  164 , upper leg section  166  and lower leg section  168 . Although not illustrated, in case the top frame  100  has been slid to the right side of the bed  1000 , the top frame  100  is capable of having the right section lifted. Here, the term “right section”  192 B similarly refers to the right portions of the head section  162 , hip section  164 , upper leg section  166  and lower leg section  168 . 
   Sliding and Lifting Mechanism 
     FIG. 7A  illustrates an embodiment of the sliding and lifting mechanism  340 . In the illustrated embodiment, the sliding and lifting mechanism  340  includes a drive screw  342  and a motor  348  for rotating the drive screw  342 . The drive screw  342  has a threaded portion and two non-threaded portions  342 A,  342 B at both sides of the threaded portion. Two traveler nuts  344 ,  345  are engaged with the threads of the drive screw  342  and capable of traveling along the drive screw  342  as the drive screw  342  rotates. In other embodiments, the drive screw  342  and traveler nuts  344 ,  345  can be replaced with functionally similar devices, in which two traveling pieces travel between the right and left sides of the bed. 
   In the illustrated embodiment, the traveler nut  344  is connected with a lifting arm  346 , which is fixed to the mattress support bars  106  of the hip section  164 . The two mattress support bars  106  are integrated together, for example, using a mechanical connector  117  connecting them from the underside thereof. In the embodiment, the lifting arm  346  is fixed to the mechanical connector  117  at about the mid-point between the two mattress support bars  106 , although not limited thereto. 
   In the illustrated embodiment, the traveler nut  345  is connected to a lifting arm  347 , which is fixed to the mattress support bars  116 . In the embodiment, the mattress support bars  116  are integrated with the two mattress support bars  118 , for example, via a mechanical connector  194  connecting them from the underside thereof. Further in the embodiment, the two mattress support bars  116  are integrated together, for example via a mechanical connector  119  connecting them from the underside thereof. In the embodiment, the lifting arm  347  is fixed to the mechanical connector  119  at about the mid-point between the two mattress support bars  116 , although not limited thereto. 
     FIG. 7B  is a view taken in the direction of VII in  FIG. 7A  and illustrates an embodiment of the connection between the lifting arm  347  and the traveler nut  345 . The lifting arm  347  has a slit  350 , in which the traveler nut  345  is engaged using a pin  352 .  FIG. 7B  further shows the hinged connection between the mattress support bar  116  and the intermediate frame  200  (slidable hinge support bar  220 , not shown) via the hinge  120 . The slit  350  of the lifting arm  347  provides a guide channel through which the pin  352  moves along when the mattress support bar  116  rotates about the axis of the hinge  120 , as will be discussed later. The traveler nut  344  and the lifting arm  346  are similarly connected. 
   Sliding Operation 
   In embodiments, the sliding and lifting mechanism  340  actuates the sliding of the top frame  1000  relative to the remainder of the bed  1000 .  FIGS. 8A and 8B  illustrate embodiments of sliding operation of the bed  1000 , which provide relative positions of the traveler nuts  345 ,  346  and the corresponding positions of the top frame  100 . In  FIG. 8A , the top frame  100  is in its normal position, i.e. the top and intermediate frames  100 ,  200  are almost totally overlapping with each other. According to embodiments, as the drive screw  342  rotates in a first rotational direction, the traveler nuts  344 ,  345  travel along the drive screw  342  in a direction, e.g. to the left of the drawing sheet. 
   Referring to  FIG. 8B , the traveler nuts  344 ,  345  have moved to the left of the drawing sheet. Accordingly, the lifting arms  346 ,  347  have moved to the left of the drawing sheet, and as a result, the top frame  100  has moved to the left of the drawing sheet too. In  FIG. 8B , according to one embodiment, the traveler nut  344  has reached the non-threaded portion  342 B (see  FIG. 8A ) of the drive screw  342 , while the traveler nut  345  is still engaged with the threaded portion. 
   In embodiments, when the drive screw  342  rotates in the opposite (a second) rotational direction, the traveler nut  344  becomes engaged with the threaded portion of the drive screw  342  again. Then, both traveler nuts  344 ,  345  begin to travel along the drive screw  342  to the right side of the drawing sheet. Accordingly, the lifting arms  346 ,  347  and the top frame  100  move to the right side of the drawing toward its normal position. Further, in embodiments, as the drive screw  342  continues to rotate in the second rotational direction, the similar operation occurs to slide the top frame  100  to the right side of the drawing sheet. 
   According to embodiments, the movement of the lifting arms  346 ,  347  to one side pushes the mattress support bars  106 ,  116 ,  118  of the hip section  164 , to which the lifting arms are attached. The mattress support bars  106 ,  116 ,  118  then push the left or right side rail  164 A,  164 B of the hip section  164 , which causes the extensions  182 A,  186 A,  188 A or the extensions  182 B,  186 B,  188 B to push the side rails  162 A,  166 A,  168 A or the side rails  162 B,  166 B,  168 B to the same direction. Further, in the embodiments where the slidable hinge support bars  220  of the intermediate frame  200  are integrated together, the movement of the mattress support bars  106 ,  116 ,  118  also cause the slidable hinge support bars  220  to slide together to the direction. Since each slidable hinge support bar  220  is hingedly attached to a mattress support bar  110 , sliding of the slidable hinge support bars  220  then causes the mattress support bars  110  to move. As a result, the top frame  100  slides to the same direction. 
   Lifting Operation 
   In embodiments, the sliding and lifting mechanism  340  further actuates the lifting of the left or right section  192 A,  192 B of the top frame  100  ( FIG. 6 ). In the configuration of  FIG. 8B , the traveler nut  344  has reached the non-threaded portion  342 B of the drive screw  342  and further contacted the housing of the motor  348 . Thus, the traveler nut  344  is not capable of traveling to the left side of the drawing sheet, and accordingly its connected components of the bed (including the top frame) cannot move to the left side of the drawing either. On the other hand, as the drive screw  342  continues to rotate in the first rotational direction from the arrangement of  FIG. 8B , the traveler nut  345  continues to travel to the left side of the drawing sheet. However, since the top frame is not moving to the left side, the force from the traveling nut  345  begins to cause the mattress support bars  116 ,  118  and the lifting arm  347  to rotate about the axis of the hinge  120 . 
     FIG. 9A  illustrate an embodiment, in which the right section  192 B (left in the drawing) of the top frame  100  is lifted by the rotational action of the mattress support bars  116 ,  118  and the lifting arm  347 . During the rotation, the pin  352  engaged with the slit  350  of the lifting arm  347  slides within the slit  350 . This is because the rotation is about the axis of the hinge  120  rather than about the axis of the pin  352 .  FIG. 9B  is a partial perspective view of the bed  1000 , in which the left section  192 A (right in the drawing) of the top frame  100  has been lifted.  FIGS. 10A ,  10 B,  10 C provide other partial perspective views of the bed  100  with different configurations. 
   Expansion of Mattress Supporting Area 
   As discussed above, the sliding of the top frame  100  to one side opens the exposed portion  280  ( FIG. 5 ) of the intermediate frame  200  and therefore expands the top surface or area of the bed  1000  on which a mattress or a person is to be supported. The additional top surface formed by the sliding helps the person stay on the bed  1000  during the lifting operation. This is because during the lifting of one section of the top frame  100 , there is only one half or less than half the top surface remains flat to support the person ( FIGS. 6A  and  6 B). Thus, the sliding feature is particularly helpful for the beds that are designed to be fitting in a space designed and/or assigned for a smaller sized bed, although not limited. 
   Certain embodiments of the invention provide the additional mattress support area using different sliding mechanisms. In one embodiment, although not illustrated, the left and right sections  192 A,  192 B of the top frame  100  are configured to slide relative to each other. For example, the left section  192 A slides to the left side of the bed  1000  while the right section  192 B remains still or slides the right side of the bed  1000 . In either example, the left section  192 A and the right section  192 B are separated so as to expand the top surface of the bed  1000  that supports a person. In this embodiment, one of the two slidable hinge support bars  220  of the intermediate frame  200  is fixed to a mattress support bar(s) belonging to the left section  192 A and the other slidable hinge support bar  220  is fixed to a mattress support bar(s) belonging to the right section  192 B. In this embodiment, the engagement and connections of the sliding and lifting mechanism  340  with the mattress support bars  106 ,  116  need to be adjusted accordingly, which will be well appreciated by ordinary skills in the relevant technology. 
   Sitting Configuration of the Bed 
   In embodiments, the bed  1000  is capable of forming a sitting configuration as illustrated in  FIG. 11 . In the illustrated configuration, the head section  362  and the upper leg section  366  have been hingedly lifted with reference to the base frame  300 , while the hip section  364  remains as in  FIG. 1 . The lower leg section  368  has been overall lifted with reference to the base frame  300 . In embodiments, the bending motions of the head section  362 , upper leg section  366  and lower leg section  368  are actuated by one or more mechanisms including at least one of electric motors, levers, mechanical joints, shafts, hydraulic actuators. In embodiments, the head section  362 , the upper leg section  366  and the lower leg section  368  are actuated by a separate mechanism. In other embodiments, two or more sections  362 ,  366 ,  368  are actuated by a single actuating mechanism. 
     FIG. 12  illustrates an embodiment of joint connections between the top, intermediate and base frames  100 ,  200 ,  300 . In the illustrated embodiment, the head section  262  of the intermediate frame  200  is hingedly connected to the base frame  300  via a hinge  440  near the hip section  264  of the intermediate frame  200 . The head section  162  of the top frame  100  is also hingedly connected to the hip section  164  of the top frame  100  at the joint  172  between the extension  182 B and the side rail  164 B. Thus, the head section  362  (including  162  and  262 ) is capable of hingedly lifted about the axes of the hinge  440  and joint  172 . 
   In the illustrated embodiment, the upper leg section  266  of the intermediate frame  200  is hingedly connected to the base frame  300  via a hinge  442  near the hip section  264  of the intermediate frame  200 . The upper leg section  166  of the top frame  100  is also hingedly connected to the hip section  164  of the top frame  100  at the join  174  between the extension  186 B and the side rail  164 B. Thus, the upper leg section  366  (including  166  and  266 ) is capable of hingedly lifted about the axes of the hinge  440  and joint  174 . 
   In the illustrated embodiment, the upper leg section  266  and the lower leg section  268  of the intermediate frame  200  are hingedly connected with each other. The upper leg section  266  and the lower leg section  268  of the intermediate frame  200  are hingedly connected with each other at the joint  444 . The upper leg section  166  and the lower leg section  168  of the top frame  100  are hingedly connected with each other at the joint  176  between the extension  186 B and the extension  188 B. Thus, the upper leg section  366  (including  166  and  266 ) is capable of hingedly bending relative to the lower leg section  368 . 
   Mattress 
     FIG. 13  illustrates a mattress assembly  400  according to an embodiment, which is designed to use with the articulating bed  1000 . The mattress assembly  400  includes a center mattress  402 , a left side mattress piece  404 , and a right side mattress piece  406 . In the illustrated embodiment, the side mattress pieces are loosely connected to the center mattress  402  along its bottom edges by strings  408 . In other embodiments, the side mattress pieces  404 ,  406  are connected to the center mattress  402  using other appropriate means such as straps, Velcro patches, etc. Also, in some embodiments, the side mattress pieces  404 ,  406  can be connected to different locations of the center mattress  402 . 
     FIG. 14A  illustrate an embodiment, in which the mattress assembly  400  placed over the bed  1000 . For the sake of illustration, the head and foot boards  316 ,  318  are not illustrated in this drawing. As shown, the center mattress  402  has about the same size as the top frame  100  in both width and length. In the illustrated embodiment, the top frame  100  is in its normal position, and the two side mattress pieces  404 ,  406  are hanging on the sides of the bed  1000 . 
     FIG. 14B  illustrates an embodiment, in which the top frame  100  has been slid to the left side of the bed  1000  as in  FIG. 5 . In the illustrated embodiment, the left side mattress piece  404  stays hanging on the left side of the bed  1000 . On the other hand, the right side mattress piece  406  has occupied the space over the exposed portion  280  (see  FIG. 5 ) of the intermediate frame  200 . Therefore, the lying area of the bed  1000  on which a person can lie has been expanded by the width of the side mattress piece  404  or the exposed portion  280 . 
   In an embodiment, the thickness  422  of the side mattress pieces  404 ,  406  are larger than the thickness  420  of the center mattress  402  approximately by the thickness of the top frame  100 . In this embodiment, since the right side mattress piece  406  is now placed over the exposed portion  280  of the intermediate frame  200 , the top surfaces of the center mattress  402  and the right side mattress piece  406  are at about the same level and there is not a large step therebetween. 
     FIG. 14C  illustrates an embodiment, in which the left section  192 A of the top frame has been lifted as in  FIG. 6 . In this configuration, the center mattress  402  is bent along the longitudinal direction of the bed. The remaining features are identical to  FIG. 14B . 
   Head Rest 
     FIGS. 15A and 15B  illustrate a head rest  410  according to an embodiment, which is designed to be used with the articulating bed  1000 . In the illustrated embodiment, the head rest  410  includes a head supporting plate  412  and a connector  414  attached to the head supporting plate  412 . Referring to  FIGS. 16A and 16B , the connector  414  is engaged with a slot formed between the mattress support bars  106  and between the left side rail  164 A (not shown) and a strap  196 , which connects the mattress support bars  106  from the underside thereof. 
   Sitting-Up-To-Side Operation 
   Using the articulating bed  1000  and optionally using the head rest  410 , a person lying on the bed can sit up with the legs hanging on one side of the bed  1000  as illustrated in  FIGS. 17A and 17B .  FIG. 18  is a flowchart for the sitting-up-to-side operation according to one embodiment. First at the step  510 , the head rest  410  is installed on one side of the bed  1000 , which is optional. Then, at the step  520 , the top frame  100  is slid to the side where the head rest  410  is installed. This is to expand the lying area of the bed  1000  by the width of the side mattress piece  404 ,  406 . Proceeding to the step  530 , a liner  910  under the person  900  is turned so as to turn that person along ( FIG. 17A ) until the person&#39;s head is supported by the head rest  410 . Next at the step  540 , the left section  192  ( FIG. 6 ) of the top frame  100  is lifted to sit the person  900  up ( FIG. 17B ) with the back and head supported and the legs hanging on the side of the bed. Following the foregoing operation, the person  900  can move to another bed or to a wheel chair alone or with a help. 
   The foregoing operation and its variations can be particularly useful to assist a person having a mobility difficulty to leave or get on the bed  1000 . The same operation can be performed in the reverse order to have the person  900  lye on the bed  1000 . 
   Liner Changing Operation 
   In addition, the articulating bed  1000  can be used to change liners without having to remove the person  900  from the bed  1000 , as illustrated in  FIGS. 19A and 19B .  FIG. 20  is a flowchart explaining placing a liner under the person&#39;s body  900 . First at the step  610  a new liner is provided for placing under the person&#39;s body  900 . Next, at the step  620 , the top frame  100  is slid to the left side (or right side) of the bed  1000 . Then, at the step  630 , the left section  192 A ( FIG. 6 ) of the top frame  100  is lifted ( FIG. 19A ). The lifting of the left section  192 A typically causes the person&#39;s body  900  to slightly turn to the right side of the bed  1000 , which creates a space between the person&#39;s back and the center mattress  402 . If a space is not created spontaneously, the attendant may turn the person&#39;s body  900  slightly to create a space between the person&#39;s back and the center mattress  402 . 
   Afterward, at the step  640 , the attendant place or pushes the new liner into the space such that a portion of the liner can reach the bottom of the space. Then, at the step  650 , the left section  192 A is lowered to make the lying area flat. In this configuration, the portion of the liner reaching the bottom of the space can be reachable from the other side of the person&#39;s body  900 . At the step  660 , the attendant pulls the portion of the liner and stretch the liner. In the alternative or in addition, the top frame  100  may be slid to the right side of the bed  1000  (left in the drawing sheet) and the right section  192 B of the top frame is lifted, which can facilitate to reach the portion of the liner and facilitate pulling and stretching the liner. 
   Removing an existing liner under the person&#39;s body  900  uses a similar operation, in which placing a new liner into the space is replaced with pushing the existing liner to the bottom of the space, so that the pushed liner could be pulled from the other side when the top frame is unlifted.