Bed with a powered width expansion wing

[0001] The subject matter described herein relates to beds of the type used in hospitals, other health care facilities and home health care settings, in particular a bed having at least one powered width expansion wing.

[0002] Beds used in hospitals, other health care facilities and home health care settings include a deck and a mattress supported by the deck. Some beds have a fixed width deck. Other beds include a fixed width center deck section, a left width adjustment wing and a right width adjustment wing. The wings can be stored under the fixed width center section, in which case the deck width equals the width of the fixed width section. The wings can also be stored partially under the fixed width center section so that they each project laterally beyond the lateral edges of the center section by a distance D1, in which case the deck width equals the width of the fixed width section plus two times the distance D1. The wings can also be deployed so that they each project laterally beyond the lateral edges of the fixed width section by a distance D2, which is greater than D1, in which case the deck width equals the width of the fixed width section plus two times the distance D2. With the wings deployed, the bed may be outfitted with a bariatric mattress, which is wider than a nonbariatric mattress, to accommodate a bariatric occupant. A typical bariatric mattress has a center section, a left width augmentation section and a right width augmentation section. Examples of augmentation sections include air filled bladders and foam inserts. The width adjustment wings are useful because with the wings deployed in order to accommodate a bariatric occupant the bed is too wide to fit through a typical doorway. When it becomes necessary to transport the occupant to a different location without removing him or her from the bed, the wings can be temporarily moved to their stored position and the mattress can be temporarily reduced in width, for example by deflating the augmentation bladders or laterally compressing the augmentation foam, so that the bed is able to fit through the doorways. Upon reaching the intended destination the bed can then be restored to its bariatric configuration, i.e. with the wings deployed and the mattress re-expanded to its bariatric width.

[0003] In a typical width adjustable bed the stored position of the wings is underneath the fixed width deck section. A caregiver deploys the wings by manually pulling them laterally away from the longitudinal centerline of the bed, and stores them by manually pushing them laterally toward the centerline. U.S. Pat. No. 7,730,562 describes a bed having powered width expansion wings. The only specific means disclosed for powering the wings are a hydraulic cylinder or a linear actuator. Such actuation devices can suffer from disadvantages such as bulk, weight and cost. Accordingly, it is desirable to devise more compact, lightweight, low cost systems for powering the expansion wings without sacrificing simplicity and reliability. It is also desirable if such systems can be retrofit onto existing beds having manually operated wings. It is also desirable if such systems or their components can be economically and easily repaired or replaced when necessary.

[0004] A bed disclosed herein comprises a fixed width section having a width and an outboard edge, a wing movably coupled to the fixed width section, a motor assembly mechanically grounded to one of the fixed width section and the wing, and a lead screw coupled to the motor assembly and to a lead screw receiver nonmovably associated with the other of the fixed width section and the wing. In practice, operation of the motor is capable of moving the wing between a deployed position in which a lateral extremity thereof is outboard of the outboard edge and a stored position in which the lateral extremity is inboard of its deployed position.

[0005] A retrofit kit as disclosed herein for upgrading a host bed having manually operable width extension wings comprises a motor assembly, a bracket for mounting the motor assembly to a bed frame, a lead screw set comprising oppositely handed lead screws each attachable to the motor assembly, and a lead screw support bracket set. Each member of the support bracket set is securable to a width extension wing of the host bed. The members of the support bracket set have oppositely handed lead screw receivers.

[0022] Referring to FIGS. 1 and 2 a hospital bed 20 includes a base frame 22 and an elevatable frame 24. A lift system represented by links 26 renders the elevatable frame vertically moveable relative to the base frame. The bed extends longitudinally from a head end H to a foot end F and laterally from a right side R (seen in the plane of the illustration) to a left side L. Casters 28 extend from the base frame to floor 40. The elevatable frame 24 includes a deck 30 comprising longitudinally distributed deck segments. The deck segments include an upper body or torso deck segment 32 corresponding approximately to an occupant's torso, a seat deck segment 34 corresponding approximately to an occupant's buttocks, a thigh deck segment 36 corresponding approximately to an occupant's thighs, and a calf deck segment 38 corresponding approximately to an occupant's calves. The upper body, calf, and thigh deck segments are orientation adjustable through angles α, β and θ. The bed also includes a controller 42 for controlling various functions of the bed and a user interface 44 in communication with the controller.

[0023] Deck segments 32, 34, 36, 38 are width adjustable segments that include wings 50 movably coupled to a fixed width center section 52. The fixed width center section has a width WF measured between left and right outboard edges 54, 56. In the illustration all four segments are width adjustable segments with both left and right wings. Alternatively, one or more wings could be coupled to only one side (left or right) of the bed. The illustrated bed has ten wings, two of which (one left and one right) are coupled to each of the seat, thigh and calf segments and four of which (two left and two right) are coupled to the upper body segment. A mattress 60 rests on the deck.

[0024] As seen in FIG. 3, a typical deck segment includes a pair of longitudinally spaced apart crossbars 64, connected together by longitudinally extending rails 68. The illustrated crossbars are in the form of C-channels having open sides 66 (seen best in FIG. 4) that face toward each other.

[0025] The bed also includes left and right head end siderails 70, and left and right foot end siderails 72. As seen most clearly in FIG. 4, each siderail is connected to a wing 50 by a center link 74 and a longitudinally split link 76 such that the siderail 70 or 72, wing 50 and links 74, 76 comprise a four bar linkage which enables a user to vertically raise and lower the siderail.

[0026] Each wing comprises a pair of longitudinally spaced apart spars 80, an inboard connector 82 (also referred to as a lead screw support bracket) spanning longitudinally between the spars at their inboard ends, an outboard beam 84 spanning longitudinally between the spars at their outboard ends, and a panel 88 extending between the spars and overlying the outboard beam. As seen best in FIG. 4, outboard edge 90 of panel 88 and outboard face 92 of beam 84 lie in approximately a common vertical plane 94 and therefore define the outboard lateral extremity of the wing. Connector 82 includes a lead screw receiver 96 comprising a threaded bore 98 (seen best in FIGS. 14-15) that penetrates through the connector. The receivers on the left and right wings are oppositely handed and each receiver is nonmovable relative to its respective wing. Each wing spar 80 nests in one of the deck segment C-channels 64 so that the spars, and therefore the wing, are laterally translatable relative to fixed width section 52. As seen best in FIG. 6, the illustrated embodiment includes bearings 102 rotatably attached to the spars to reduce resistance when the wings translate relative to the fixed section. Other types of interfaces between the spars and the C-channels, such as rollers, could also be used.

[0027] Referring additionally to FIG. 7, the bed also includes a motor assembly 110 comprising an electric motor 112 and a gear train 114, such as a worm and pinion, housed in a housing 116. The motor assembly is mechanically grounded to fixed width section 52. Specifically the motor assembly is bolted to a motor mounting bracket 120 which itself is bolted to rail 68. A coupling shaft 124, which is rotatably driven by the gear train, projects out of the left and right sides of housing 116. One end of a lead screw 126L having a rotational axis 128L is coupled to one end of shaft 124, and therefore to motor assembly 110, by a coupling collar 130 and a pair of R-pins 134. The other end of lead screw 126L is received in receiver 96 of left wing 50L. Another lead screw 126R is coupled to the other end of shaft 124, and therefore to motor assembly 110, by another coupling collar 130 and an additional pair of R-pins 134. The other end of lead screw 126R is received in receiver 96 of right wing 50R so that its rotational axis 128R is colinear with axis 128L. The colinear axes 128L, 128R define a common rotational axis for the lead screws. Lead screws 128L, 128R are oppositely handed as are the lead screw receivers in the left and right wings. Each lead screw and its receiver are same-handed.

[0028] FIG. 8 schematically show the above described kinematic arrangement in which the motor assembly 110 is mechanically grounded to fixed width section 52 and the lead screw receivers are nonmovably associated with each wing. FIG. 9 shows a kinematic inversion in which a motor assembly 110 is mechanically grounded to each wing 50 and the lead screw receivers are nonmovably associated with fixed width sections 52. In the architecture of FIG. 9 coordination of the direction of movement of the width expansion wings can be accomplished with oppositely handed lead screws or with opposite motor rotational directions.

[0029] In practice, operation of the motor in a first rotational direction moves the left and right wings in unison in a laterally outboard direction. Operation of the motor in a second rotational direction, opposite that of the first rotational direction, moves the wings in unison in a laterally inboard direction. In particular the motor can move the wings between a deployed position in which the lateral extremity 92 of the wing is outboard of the outboard edge 56 or 58 of the fixed width section 52 (e.g. FIGS. 2-5A) and a stored position in which the lateral extremity 92 is inboard of its deployed position (FIGS. 5B, 10). When the wing is stored its outboard extremity 94 may be outboard of, inboard of, or substantially laterally aligned with outboard edge 56 or 58 of fixed width section 52.

[0030] FIG. 11 is a schematic representation of the above described architecture having four deck segments, all four of which are width adjustable. The motor (or a set of motors in the variant in which the motors are mechanically grounded to the wings) is associated with and dedicated to one and only one of the four segments 32, 34, 36, 38. In other words each width adjustable segment has a dedicated motor assembly associated with it for moving the wings coupled to that same segment. In general, in a bed having at least two deck segments, and in which at least two of those segments are width adjustable segments, each segment is serviced by its own dedicated motor assembly or assemblies.

[0031] FIGS. 12-13 show an alternative in which the wings of at least two of the width adjustable segments are movable by a common motor assembly. Specifically, a motor assembly 110 is mechanically grounded to center section 52 of thigh deck segment 36. Wings 50 of segment 36 are master wings driven directly by the common motor assembly. Wings 50, of the seat and calf segments 36, 38 are slave wings connected to the master wing by a link 138 which conveys the lateral motion of the master wings to the slave wings. The slave wings are considered to be indirectly driven because the master wings intervene between the motor assembly and the slave wings. The wings of the upper body section of FIG. 9 are serviced by a motor dedicated to the upper body section.

[0032] The foregoing explanation and accompanying illustrations are directed to beds manufactured with the powered width adjustment feature. However a retrofit kit may be provided for upgrading beds having manually operable width expansion wings. As seen in FIGS. 14-15 a retrofit kit includes at least a motor assembly 110, a motor mount bracket 120 (FIG. 14) or 140 (FIG. 15) for mounting the motor assembly to a bed frame, a lead screw set comprising oppositely handed lead screws 126L, 126R each of which is attachable to the motor assembly, and a lead screw support bracket set comprising a pair of lead screw support brackets 82. The members of the lead screw support bracket set have oppositely handed lead screw receivers 96 and are securable to a width extension wing e.g. by welds or bolts. Other hardware such as a coupler shaft 124, coupling collars 130, R-clips 134 and other fasteners may also be part of the kit. Although FIGS. 14-15 show several kit components as individual parts, certain kit components, such as the motor assembly and motor mount bracket, can be preassembled to each other rather than provided as individual components.

[0033] FIGS. 14 and 15 show two different styles of motor mount brackets. Motor mount bracket 120 of FIG. 14 is configured to attach the motor assembly to a preexisting, longitudinally extending rail 68 of the bed frame, for example rail 68 of FIG. 3. Motor mount bracket 140 of FIG. 15 is configured to span longitudinally between crossbars 64 of the bed frame. The ends of brackets 140 are secured to the crossbars by bolts (not shown). Bracket 140 is useful if the deck segment or segments of interest do not have a suitable, preexisting rail 68 to which the bracket can be attached. FIGS. 16-18 are views of bracket 140 shown in the context of a bed frame but with the mounting bolts not illustrated.

[0034] Although this disclosure refers to specific embodiments, it will be understood by those skilled in the art that various changes in form and detail may be made without departing from the subject matter set forth in the accompanying claims.