United States Patent 3628200
A hospital-type bed including a frame with head and foot members each having tubular upright corner posts connected by upper and lower horizontal members of channel shape which are braced intermediate their ends by a wider upright member of channel shape. A panellike cover plate is detachably secured to each member. Each corner post is open at its lower end and telescopingly receives an upright, floor-supported leg. A single elongated threaded shaft is journaled in the upper horizontal member of each end frame and is rotatable by a crank applicable to either end of the shaft. Nuts on the shaft are slidable lengthwise of the upper horizontal member by rotation of the shaft. An individual cable is secured at one end to each nut and extends over sheaves in the frame and is secured at its other end to the upper end of a floor-supported leg. When the crank is actuated to rotate the shaft, the cables are taken up or paid out to raise or lower the end frame on the telescoping legs. A friction pawl on each leg automatically engages the associated corner post to hold the leg against dropping from the post when the leg and cable do not support the end frame.
Foster Bros. Manufacturing Company (St Louis, MO)
A61G7/012; (IPC1-7): A61G7/00
Field of Search:
Gilliam, Paul R.
1. A hospital bed comprising head and foot frames, side rails connecting the head and foot frames, and a spring frame supported by the side rails, floor-supported leg members, corner posts on each head and foot frame, the corner posts receiving the leg members and being vertically slidable thereon, the head and foot frames having an upper portion, a horizontal rod housed in and journaled in said upper portion of each frame, the rod having threaded portions in opposite directions from the midpoint toward each end thereof, a nut on each threaded portion, each nut being nonrotatable and slidably engaging the upper portion of the frames, a pair of vertically disposed sheaves journaled in the head and foot frames below the inner end of each threaded portion, and a side sheave journaled on each lower side portion of each head and foot frame adjacent each corner post thereof, individual cables secured at one end to each nut with the other end secured to an upper portion of each floor-supported leg member and passing over the nearer pair of vertically disposed sheaves and side sheave, and independent means exteriorly of the head and foot frames to independently rotate each rod to cause the nuts on each rod to move along each rod to pull or release each cable to raise and lower the head and foot frames independently and cause the spring frame to be angularly disposed with respect to the head and foot frames or to raise and lower the spring frame with respect to the floor.
2. A hospital-type bed structure as described in claim 1 in which the head and foot frames are substantially hollow and the legs, threaded rod, sheaves and cables are enclosed within the frames.
3. A hospital-type bed structure as described in claim 1 in which the corner posts are connected by vertically spaced horizontally extending upper and lower cross members of channel section, there being a vertically extending member of channel section connecting the intermediate portions of said horizontal members, and a readily detachable panel covering the open sides of said lower and vertical channel section members and enclosing the cables and sheaves mounted therein.
4. A bed as described in claim 1 in which each cable anchor comprises a pawl pivoted at one end on the upper portion of a leg, a spring thrusting the swinging end of each pawl transversely of the leg into engagement with an inner face of the associated corner post, each pawl being clear of said post when the corner post is supported by said cable but thrust against the inner face of the corner post by the spring if the bed frame end structure is lifted independently of the cable to relieve the cable and pawl of their normal load.
BACKGROUND OF THE INVENTION
Beds for use in hospitals or elsewhere for invalids require frequent vertical adjustment of the height of the spring and mattress at either or both ends of the bed. Such adjustment is usually effected by a crank-operated mechanism which selectively raises or lowers one or both ends of the bed on telescoping legs which extend downwardly from the bottom of each tubular corner post of the bed frame. The operation of the ends independently of each other permits the spring and mattress surface to be placed at an angle, with the head end lower than the foot end or vice versa. These positions are often necessary for treatment of certain circulatory problems or other ailments and are known as the Trendelenberg and reverse Trendelenberg positions, respectively. Prior designs effected the vertical adjustment of the telescoping legs through a series of shafts and bevel gears connected to individual screws in each leg. Such mechanism is not only costly to manufacture but, because of friction in the shaft and gear train, requires excessive effort to operate. Because of the inherent nature of the gear train design, the operating cranks are located at a low position which requires the attendant to assume a bent-over awkward and uncomfortable position. Because of the complexity of the gear train mechanism, frequent breakdowns occur causing troublesome service problems. Among the objects of the present invention are to provide a hospital bed with simplified, economical elevating mechanism enclosed within the end frames which is easy to operate, is not subject to breakdowns and service problems, and in which head, foot and spring units can be disassembled easily for transporting the bed from one location to another, and to avoid accidental dropping the telescoping legs from the corner posts, if any part of the bed frame is lifted manually or supported directly otherwise than by the floor-engaging legs.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an isometric view of a hospital-type bed embodying the invention.
FIG. 2 is a vertical section of the bed frame on line 2-2 of FIG. 1 with a finish panel removed to better illustrate the raising and lowering mechanism.
FIG. 3 is a vertical section on line 3--3 of FIG. 2.
FIG. 4 is a vertical section through the right-hand corner post and the telescoping leg shown in FIG. 2 and showing the elements suspending the corner post from the leg.
FIGS. 5 and 6 are detail horizontal sections on lines 5--5 and 6--6 of FIG. 4.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The bed frame includes a head structure 1, a foot structure 2 and side rails 3 which carry the spring and mattress. The head and foot have tubular corner posts 4 with slotted brackets 5 receiving hooks on the ends of the side rails as is customary.
Each head and foot structure includes an upper horizontal member 6 of channel cross section extending between corner posts 4 with its web disposed horizontally and its flanges extending upwardly. A cap 7 is removably secured to the open side of channel member 6. A lower horizontal member 8 of channel cross section extends between the corner posts with its web disposed vertically and its flanges extending outwardly of the bed. An upright member 9 of channel cross section extends between members 6 and 8 intermediate their end and with its flanges extending outwardly of the bed. An upright panel 10 overlies the open sides of channel members 8 and 9 and is detachably secured to members 6 and 8 by screws 11.
The bed frame is supported on four legs 13 each telescopingly received in one of corner posts 4 and supporting the bed frame by height adjustment mechanism concealed in a housing formed by the corner posts and the channel members 6, 8, 9, and panel 10. This mechanism, duplicated at heat and foot, includes a horizontal rod 18 extending the length of each upper cross member 6 and journaled therein. A crank 19 may be applied to either end of the rod to rotate it manually. The rod has oppositely threaded portions extending respectively from its middle toward each corner post. A nut 20 on each threaded portion of the rod slidably engages member 6 and rotation of the rod by crank 19 feeds the nuts simultaneously away from each other or toward each other according to the direction of crank rotation.
A pair of sheaves 21 are journaled in the upper end of upright member 9. Another pair of sheaves 22 are journaled on the intermediate portion of lower cross member 8. A sheave 23 is journaled on each outer end portion of member 8.
An individual cable 35 is anchored at one end to each nut 20 and extends horizontally therefrom over a sheave 21, then downwardly and over a sheave 22, then horizontally over a sheave 23 and through an opening N (FIG. 4) in the side of corner post 4 and then upwardly along a depression D in the adjacent side of leg 13. The upper end of the cable is secured to the lower end of a friction pawl 27. A pin 28 pivots the upper end of the pawl to the upper portion of the leg. A torsion spring 29 tends to thrust the swinging end of the pawl into the inclined position shown in FIG. 4 and holds the leg against dropping from the post. Normally the weight on cable 35 swings the pawl to the vertical position shown in broken lines in FIG. 4.
If a portion of the bed frame near a leg is lifted from the floor and the corresponding cable is relieved of its load, the torsion spring thrusts the lower end of the pawl against the inner face of the pawl into frictional engagement with the inner face of the post and holds the leg against dropping if the bed is lifted. When the weight of the bed frame is again transferred to cable 35 the latter will pull pawl 27 to the vertical position and it does not resist relative movement of the leg and the corner post as induced by operation of crank 19 and the cables. Also spring 29 and pawl 28 tend to prevent lateral play between the upper end of the telescoping leg and the bed corner post. The lower portion of each corner post has indentations 32 in its walls opposing the outer faces of the legs and preventing noticeable lateral wobble between them. Strips or buttons of plastic material may supplement or be substituted for indentations 32 to effect the same result.
All of the bed frame raising and lowering mechanism at the head or foot of the bed is housed within the adjacent end structure, thus presenting a neat appearance and being free of entanglement with the bedclothes or with the fingers or garments of people who are in or about the bed and providing for ready assembly and disassembly of a bed without difficulty because of cables or shafts between the head and foot.