Description:
BACKGROUND OF THE INVENTION
Adjustable beds useful in hospitals and generally in the handling of bedridden patients have a mattress supporting assembly divided into a plurality of sections, several of which may be pivotally rotated to elevate the head and/or thigh portion or the mattress and therefor a patient lying thereon. In conventional beds, when the head portion is pivoted upward, the distal end is concurrently moved toward the foot end. That is, the head portion while desirably moving up or down also moves toward or away from the foot portion of the bed. If some other hospital furniture, such as, for example, a bedside stand is positioned to accomodate a patient while in a prone position, it will not be properly positioned to accomodate a patient whose head has been elevated and thus moved toward the foot end of the bed and consequently away from the stand.
One early solution to this problem is exemplified by British Pat. No. 839,310, published June 29, 1960. In FIG. 3 a mattress frame comprising sections 1 and 3 pivotally attached to opposite ends of a third mattress frame portion 2 is longitudinally movable relative to a base frame 12 on rollers 29 being constrained only by link 13 pivotally attached at opposite ends to frame 1 and leg 16 of frame 12. As the mattress frame is caused to move horizontally to the right, as illustrated in FIG. 3, mattress frame 1 is pivoted upward to the position shown in phantom while the distal end of mattress frame 1 remains substantially horizontally motionless.
Another solution to the problem is exemplified by U.S. Pat. No. 3,237,212, issued Mar. 1, 1966, to Hillenbrand et al. In FIG. 2, a frame 11 is longitudinally movable along a frame 10, constrained only by link 178 pivotally attached at its opposite ends to frame 10 and to mattress frame 13. Frame 13 is pivotally attached at 94 to mattress frame 12, which is secured to frame 11. As mattress frame 13 is pivoted about 94 by means attached to frame 10, link 178 constrains the distal end 93 (FIG. 1) of frame 13 to substantially only vertical movement. Such an arrangement may be practical in a situation where there is no need to also move frame 11 vertically relative to frame 10. When such vertical movement is desirable, such as to raise and lower the various sections of the mattress frame and therefore a patient lying thereon, the Hillenbrand et al. mechanism is not suitable.
SUMMARY OF THE INVENTION
An adjustalbe bed comprises first, second, third, and fourth frames. The second frame lies generally parallel to and is movable along the elongated first grame. The third frame is pivotally coupled to the second frame, the pivotal axis being perpendicular to the length dimension of the first frame. The fourth frame is movable relative to the second frame in a direction parallel to the length dimension of the first frame but is prevented from movement along the first frame. A motion translating means is included for translating relative motion between the second and fourth frames into pivotal motion of the third frame. Another means is included for creating longitudinal motion of the second frame relative to the first frame for causing the third frame to pivot about its axis.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a perspective view of an adjustable bed with head and foot ends elevated according to the present invention;
FIGS. 2 and 3 are elevational cross-section views along line AA of FIG. 1, showing respectively a portion of an adjustable bed in the lowered and raised positions.
DETAILED DESCRIPTION
Referring to FIG. 1 of the drawing, there is shown an adjustable bed generally designated 10, of the type used in hospitals, having an elongated base frame 12, which is supported on casters 14 adjacent each of the four corners thereof only one being fully illustrated. The base frame 12 includes oppositely disposed, parallel channel bars 16 only the right one being visible. Movable along each channel bar 16 are two rollers 22 (shown in phantom) each rotatably mounted on the lower end of a lever arm 24, and located generally at opposite ends of channel bar 16. The lever arms 24 are secured to opposite ends of a cross rod 38. Each cross rod 38 is rotationally mounted near its ends in a sleeve bearing 30, there being four such sleeve bearings, only one being readily visible in FIG. 1. Bearing sleeves 30 are attached near each end of the undersides of parallel channel bars 34 forming the side railings of a second elongated frame generally designated 36.
Secured to each cross rod 38 are a pair of links 44, which extend upwardly and are pivotally attached at their upper ends to a connecting link 46. The link 46 is pivotally coupled near its midpoint to one end of an internally threaded tube 48. Tube 48 is threadedly engated with a threaded rod 50, extending longitudinally near the center of the bed. One end of rod 50 is connected to a gear box 66 to be rotated thereby. Gear box 66, which is secured to second frame 36, is operatively connected to a reversible electric motor 68. A crank receiving pin 70, which is part of gear box 66, is adapted to receive a crank (not shown). When motor 68 is not operational for any reason, the gear box may be manually cranked to effect the same purpose. Alternately in a less expensive hospital bed, motor 68 may not be supplied.
By means of the above described mechanism, the entire second frame 36 may be moved toward and away from base frame 12, i.e., raised or lowered. When the second frame is to be raised, motor 68 directed by electric control means (not shown, but described in detail in U.S. Pat. No. 3,644,945, issued Feb. 29, 1972, to the instant inventor as joint inventor) causes rod 50 to rotate in a direction to move tube 48 and thus connecting link 46 toward the gear box 66 (as illustrated in FIG. 1), that is toward the foot end 71 of the bed. The movement of connecting link 46 causes cross rods 38 to pivot in bearings 30, causing levers 24 to move toward the upright position, thereby raising frame 36. When the motor is reversed, causing tube 48 to move away from gear box 66, that is toward the head end 73 of the bed, levers 24 move toward the horizontal position, thereby lowering frame 36. It should be noted that but for the constraints of mechanisms to be described, frame 36 is free to move longitudinally relative to frame 12 on rollers 22. As mentioned in the aforementioned U.S. Pat. No. 3,644,945, a more complex raising and lowering mechanism may be utilized which raises one end of the bed more than the other. Such a mechanism may be substituted for the one described herein. Regardless of which mechanism is used, the two frames of the bed thus described (i.e. frames 12 and 36) are considered to be generally parallel for purposes of the claims which follow.
Independent of the vertical position of frame 36, the various sections of a third frame generally designated 106, which are attached directly or indirectly to the second frame, are adjustable relative to each other. Frame 106, which supports the mattress (not shown) on which a patient lies, comprises a head section 108, a seat section 110, and a leg section comprising a knee section 112, and a foot section 114. The seat section 110 is secured to frame 36 by means of angle brackets 115. The head section 108 is pivoted to the seat section at 116, while the knee section 112 is pivoted thereto at 120. The foot section 114 is pivoted to the knee section 112 at 122. Nothing further will be said about the operation of the knee section 112 and foot section 114, nor about the mechanisms for adjusting these sections. For further information and description on these topics, along with a detailed description, the reader is directed to the aforementioned U.S. Pat. No. 3,644,945.
A "U" shaped fourth frame generally designated 300 includes parallel rods 302 secured at one end to a common square bar 303 and slidably mounted in bushings 304 secured to channel bars 34. There are two bushings 304 on each channel bar 34 (only the bushings on the left channel bar 34 being visible). This arrangement permits frame 300 to move only longitudinally relative to frame 36.
An internally threaded tube 306 is secured at one end to frame 300 and at the opposite end threadedly engages a threaded rod 308. The opposite end of rod 308 is coupled to a gear box 310 having a crank receiving pin 312. The gear box is normally driven by a reversible motor 314. When motor 314 is operated in one direction by electric controls (not shown but similar to those described in the aforementioned U.S. Pat. No. 3,644,945, in connection with the raising and lowering of the head section) the rotation of rod 308 causes relative movement of frame 300 toward motor 314; that is, toward the foot end of the bed. Similarly, when motor 314 is operated in the opposite direction, relative movement of frame 300 away from the foot end of the bed occurs. As will be described shortly, frames 36 and 106 move relative to frame 12 while frame 300 remains stationary.
A pair of motion translating mechanisms generally designated 316 comprises a pair of arms 318 and a pair of arms 320. Each arm 318 is pivotally attached at 322 to a rod 302 and has rotationally attached thereto at the opposite end a roller 324, which rides along a channel member 326 attached to head section 108. Each arm 320 is pivotally attached at 328 to a channel bar 34 of the second frame 36 and pivotally attached at 330 to its associated arm 318 at a point intermediate the ends thereof. Because of the mechanism just described as frames 36 and 300 are moved relatively closer together, the head section is elevated while as the two frames are moved relatively further apart the head section is lowered. As mentioned in the background section, it is most desirable that the distal end 332 of head section 108 not move horizontally relative to a reference object while the head section 108 is raised or lowered. This is accomplished in accordance with the embodiment illustrated in FIG. 1 by requiring that frame 300 remain horizontally stationary relative to frame 12 and by establishing the lengths and attachment points of arms 318 and 320 so that as the distal end 332 of frame section 108 is raised and lowered, it remains horizontally stationary relative to frame 300. Since frame 36 and thus frame 300 must be allowed to move vertically relative to frame 12, a pair of connecting rods 340 (only one being illustrated) is pivotally attached at 342 to frame 12 and pivotally attached at 344 to frame 300. Attaching points 342 may be positioned sufficiently near the foot end of the bed, such that the arcuate path followed by 344 as the bed is raised and lowered is made very slight and there is no substantial horizontal movement of the bed.
In operation, referring to FIGS. 1, 2, and 3, the latter being cross sections generally along line AA of FIG. 1 of the head end of the bed with the head section 108 being fully lowered and fully raised respectively, when it is desired to raise the entire bed, that is, to raise frame 36 and thus frames 106 and 300, relative to frame 12, motor 68 is operated to rotate levers 24 counter-crosswise (as illustrated) to a relatively vertical position. Because of the attachment of rods 340 to frames 12 and 300, frames 36 and 106 merely move substantially vertically while rollers 22 move toward the head end of the bed. There is thus no substantial horizontal movement of head section 108.
When it is desired to raise the head section 108 motor 314 is operated to move frame 36 longitudinally relative to frames 12 and 300 toward head end of the bed 73, rollers 22 allowing the horizontal motion. Rollers 324 are thereby caused to elevate causing the distal end 332 of frame 108 to rise substantially only vertically. Refer to FIGS. 2 and 3 where headboard 350 shown in phantom attached to frame 300 may serve as a reference for the position of the various components. As mentioned previously, the lengths of arms 318 and 320 and their attaching points must be properly chosen to achieve the desired result of no horizontal motion of the distal end of head section 108, while it is being raised and lowered.
The particular parameters for a given application may be calculated by a competent mechanical design engineer as is known in the state of the art or may be developed by trial and error.
It is, of course, not necessary that motion translating mechanisms 316 be exactly as shown. For example, if arm 318 is pivotally attached to frame 108 at 324, as well as pivotally attached before 300 at 322, arm 320 is not needed. Alternatively, appropriate cam members on rods 302 may cooperate with cams on 108 to affect the desired motion.