Adjustable bed

Abstract

 Adjustable bed comprising an under-mattress consisting of a rigid frame, on which a head end part and a foot end part are pivotally fastened individually between the ends and over which a top mattress can be laid, while each end part is provided with a raising device adapted to be driven by a device with the aid of an operating rod for the purpose of adjusting the inclination of the end part, characterized in that one drive device (15,16) is provided for the two end parts (3, 4), and that one raising device (6) is connected to the operating rod (13) for direct movement and the other (7) is connected to said rod for movement via a lost-motion mechanism (23, 24), in such a manner that one end part can first be raised, while the other end part is raised by continuing the operation of the drive device. Since it is realised that in practice always first the foot end part is raised, to avoid slipping down, before the head end part, the above described simple drive mechanism can be used, instead of complicated known devices, without sacrificing comfort, thereby improving ease of operation (Figure 1c).

Description

[0001] The invention relates to an adjustable bed comprising an under-mattress consisting of a rigid frame, on which a head end part and a foot end part are pivotally fastened individually between the ends and over which a top mattress can be laid, while each end part is provided with a raising device adapted to be driven by a device with the aid of an operating rod for the purpose of adjusting the inclination of the end part.

[0002] Various forms of adjustable beds of this kind are known. There are beds in which the head end part and the foot end part are adjustable, independently of one another, by means of separate raising devices and drive devices. These beds are excellent in respect of ease of operation and comfort, but they are expensive because of the separate drives. Other beds are known in which only one drive device is used and in which the pivoting movements of the head end part and foot end part are permanently coupled together. These devices are of simpler construction and therefore less expensive, but lack some of the comfort of the previously mentioned adjustable beds.

[0003] The invention now seeks to provide an adjustable bed which, while retaining the constructional simplicity of the type last mentioned, combines the comfort and ease of operation of the bed first described above.

[0004] To this end, the bed described in the first paragraph above is according to the invention characterized in that only one drive device is provided for the two end parts, and that one raising device is connnected to the operating rod for direct movement and the other is connected to said rod for movement via a lost-motion mechanism, in such a manner that one end part can first be raised, while the other end part is raised by continuing the operation of the drive device. As a rule it will be preferable with the adjustable bed described above, in which the maximum adjustable inclination of the longer foot end part is limited and that of the shorter head end part amounts to a multiple thereof, for the lost-motion mechanism to be disposed between the operating rod and the head end part, in such a manner that, starting from the horizontal, fully flat position, the foot end part is first pivoted up and that the head end part is raised only on completion of the lost-motion stroke.

[0005] Although with the abovedescribed bed according to the invention there is slightly less freedom of movement than with the known bed first described above, this is no disadvantage because a person lying on the bed will never want the head end to be raised first, in order to ensure that that person cannot slide downwards. In practice the first step will be to raise the foot end before the head end is brought into a possibly far steeper position, because then slipping down will be impossible. Because of accepting this logical limitation, the bed according to the inventlon is of simpler construction and nevertheless very comfortable and convenient to operate.

[0006] The preferred embodiment is characterized in that the raising device for the foot end part is so constructed that as the operating rod continues its movement, the foot end part is first pivoted upwards with decreasing angular speed and that, after the head end part has started to move on completion of the lost-motion stroke, the raising of the foot end part will have practically ceased, while on further movement of the operating rod it is maintained approximately in its highest position. Practice has meanwhile shown that the desired maximum inclination of the foot end appears to be slight and very constant irrespective of the desired inclination of the head end. It is therefore desirable during further raising of the head end part, to maintain the foot end part practically in the same maximum, but only little inclined position.

[0007] In adjustable beds in which a so-called knee-bending device is provided, it is advantageous for this device to be coupled to the operating rod via its own lost-motion mechanism. The straight foot end part is thus first pivoted upwards through a small angle before the knee-bending pivot and the head end part are moved either one after the other or simultaneously.

[0008] The moment when, or more correctly the angle of inclination of the foot end part after which the head end part and the knee-bending pivot, if the latter is provided, are brought into movement is preferably adjustable, and according to a preferred embodiment provision is made for each lost-motion mechanism to have its own individually adjustable end position for the free stroke on the foot end side. The construction adopted to solve this problem will be further explained in the following description of the drawings and the claims.

[0009] In the above description it is not indicated whether the operating rod rotates or makes a translatory movement substantially in the longitudinal direction. Both movements are possible, because lost-motion mechanisms are well known both for translation and for rotation.

[0010] The invention will be explained in greater detail with the aid of the following description of the accompanying drawings showing as an example a preferred embodiment of the invention.

Figure 1 shows schematically an adjustable bed according to the invention in three different positions, a, b, c, while Figure Id shows an alternative embodiment.

Figure 2 shows on a larger scale a detail of the adjustable bed according to the invention.

Figure 3a, b shows an alternative form of construction of the foot end.

[0011] 1 designates generally the so-called under-mattress, which can be laid directly on the floor with the aid of legs (not shown). However, the under-mattress 1 is frequently placed in a bed frame (likewise not shown), which is placed on the floor. The under-mattress 1 forms the carrier of a top mattress (not shown). In adjustable beds the under-mattress 1 often consists of a rigid frame 2, on which, in its middle region, a foot end part 3 and a head end part 4 are pivotally connected at 5. In the drawings the pivot connection is shown only schematically, because known constructions can be used for this purpose. As usual, the foot end part 3 is longer than the head end part 4. 6 designates generally the raising mechanism for the foot end part 3. It consists of a bent lever having arms 8 and 9 and pivotally connected at 10 to the rigid frame 2. At the free end of the arm 8 a supporting roller 11 is rotatably mounted, being adapted to move over a track formed by the lower edge of the foot end part 3. The free end of the other arm 9 carries a pivot pin 12, to which an operating rod 13 is pivotally connected. The operating rod 13 extends from the foot end of the rigid frame 2 in the direction of the head end, where it is pivotally connected by a pivot pin 14 to a threaded spindle 15 of a drive motor 16. The motor 16 is in turn pivotally fastened by means of a pin 17 to a bracket 18, which itself is fastened to the head end of the rigid frame 2. During operation the casing of the motor 16 is stationary and the inner part rotates and thus drives a nut adapted to move the spindle 15 in and out.

[0012] The head end part 4 is tilted up by the raising mechanism 7, which is of similar construction and consists of a bent lever having arms 19 and 20. This lever is pivotally fastened at 21 to the rigid frame 2. The free end of the arm 19 carries a rotatable roller 22, on which the underside of the head end part rests, thus forming a track for the roller 22. The free end of the other arm 20 of the lever carries the pivot pin 23, which is inserted into a slot 24 in the operating rod 13.

[0013] The action of the device according to the invention is illustrated in Figures la, b, c. In Figure la the two end parts are shown in the completely flat position on the rigid frame 2. The two lever arms 9 and 20 lie in a position in which they are pivoted as far as possible to the left in the figures. Because of the bend in the two levers 6 and 7, the rollers 11 and 22 respectively, together with the corresponding arms 8 and 9, are completely folded away into the rigid frame 2. The operating rod 13 is in its farthest left position, with the threaded spindle 15 screwed as far as possible out of the drive device 16. The slot 24 is situated substantially on the left-hand side of the pin 23 at the free end of the arm 20 of the raising device 7 for the head end.

[0014] Figure lb shows a position in which the motor 16 has retracted the threaded spindle 15 over a distance of less than half the stroke, whereby the short lever arm 8 near the foot end has been turned so far in the upward direction that the supporting roller 11 has not only pivoted the foot end part 3 upwards through a relatively small angle x, but at the same time has almost reached its maximum raised position. In this position the slot 24 has been moved so far to the right that the pin 23 of the raising device 7 for the head end has come close to the end of the slot. When the action of the drive motor 16 continues, the raising device 7 will also be operated because the pin 23 will bear against the end of the slot 24. This is illustrated in Figure lc. Because the arm 19 of the raising device 7 is many times as long as the arm 8 of the raising device 6, the pivoting angle f of the head end part 4 can be considerably greater than that of the foot end part 3. For this purpose the bottom arms 9 and 20 are approximately equal in length. In this position of maximum inclination the threaded spindle 15 is screwed completely into the drive device 16. At the same time the operating rod 13 has increasingly approached the extended position in relation to the bottom lever arm 9 at the foot end. The roller 11 under the foot end part 3 has passed meanwhile its highest position, but the maximum attainable lifting angle d of the foot end part 3 has not been altered considerably thereby.

[0015] An operating and drive system 13, 14, 15 and 16 is illustrated and described above in which the parts make translatory movements. It will however be clear to the expert that a rotating drive system can equally well be used, in which case the pins 12 and 23 can be replaced by nuts moving on a rotating spindle 13 provided with a screwthread. The lost-motion mechanism 23, 24 can in this case also be in the form of a pin and slot combination or of a known rotary lost-motion device.

[0016] Figure Id shows a much used construction of an adjustable bed in which the foot end part 3 contains a knee-bending pivot joint 31. The raising device 30 for this arrangement is similar in construction to the raising device 6 shown in Figures la, b and c. Once again, a bent lever is pivotally fastened at 34 to the rigid frame 2. The top arm 32 is provided with a roller 35, which operates the knee-bending joint 31. The bottom lever arm 33 carries at its end a pin 36, which is received in a slot 37 in the operating rod 13. As can be seen in Figure ld, the position of the pin 36 in relation to the rod 13 provided with the slot 37 coincides with that of the pin 23 and the slot 24 at the head end. The moment at which the knee-bending joint 31 comes into action is similarly determined by the position of the left-hand end of the slot 37 in relation to the position of the pin 36, exactly as was described for the raising device 7 at the head end. It will be clear that it is not necessary for the two devices 7 and 30 to come into action simultaneously in the same position as shown in Figure lb.

[0017] It is therefore advantageous for the operative end of the slots 24 and 37 to be made adjustable. This is illustrated in Figures 2a and 2b, the latter being a plan view of the operating rod 13 in the region of the slot 24 shown in Figure 2a. The pin 23 end of the slot 24, but against a pin 35. This pin is adjustable in relation to the position of the slot 24, for example with the aid of a number of pin holes 26, as shown in the figure. When the bed is in the completely lowered position, the pin 25 can be placed at choice in one of the holes 26. The moment at which the head end part 4 begins to be raised can be adjusted in relation to the raised position of the foot end part 3, and thus the maximum attainable angle of inclination of the head end part 4 can be similarly adjusted. The same structure is applicable as well for the knee-bending pivot 30.

[0018] The illustrated drive and operating means can also be made hand-driven instead of motor-driven.

[0019] Fig. 3a, b shows a curved track on the underside of the foot end part 3 for the support roller 11. This track comprises two downwardly extending, rounded projections or cams 3₁ or 3₂. During the raising movement the support roller 11 first runs against the cam 3₁, so that a desired lift-time characteristic can be achieved in a simple manner. The roller 11 is situated on the top of the cam 3₁ at the moment when the lost-motion stroke of the slot 24 has ended, that is to say in the position in which on the continuation of the operation of the motor 16 the head end part 4 also starts to be raised.

[0020] If the path between the cams 3₁ and 3₂ and the height of the second cam 3₂ are given the correct shape (circular path about the pivot point 10), the foot end part 3 will retain exactly the same inclination when the angle _/3 of the head end part 4 is reached. If the path 3₁ - 3₂ is made interchangeable, any desired lift-time characteristics can be obtained in a simple manner.

Claims

1. Adjustable bed comprising an under-mattress consisting of a rigid frame, on which a head end part and a foot end part are pivotally fastened individually between the ends and over which a top mattress can be laid, while each end part is provided with a raising device adapted to be driven by a device with the aid of an operating rod for the purpose of adjusting the inclination of the end part, characterized in that one drive device (15, 16) is provided for the two end parts (3, 4), and that one raising device (6) is connected to the operating rod (13) for direct movement and the other (7) is connected to said rod for movement via a lost-motion mechanism (23, 24), in such a manner that one end part can first be raised, while the other end part is raised by continuing the operation of the drive device.

2. Adjustable bed according to Claim 1, of which the maximum adjustable inclination of the longer foot end part is limited and that of the shorter head end part amounts to a multiple thereof, characterized in that the lost-motion mechanism (23, 24) is disposed between the operating rod (13) and the head end part (4), in such a manner that, starting from the horizontal, fully flat position (Figure la), the foot end part (13) is first pivoted up and that the head end part (4) is raised only on completion of the lost-motion stroke.

3. Adjustable bed according to Claim 1 or 2, characterized in that the raising device (6) for the foot end part (3) is so constructed that as the operating rod (13) continues its movement, the foot end part (3) is first pivoted upwards with decreasing angular speed and that, after the head end part (4) has started to move on completion of the lost-motion stroke, the raising of the foot end part (3) will have practically ceased, while on further movement of the operating rod (13) it is maintained approximately in its highest position.

4. Adjustable bed according to one or more of the preceding claims, wherein the foot end part is provided with a so-called knee-bending device, characterized in that said device (30) is coupled to the operating rod (13) via its own lost motion mechanism (36, 37).

5. Adjustable bed according to one or more of the preceding claims, characterized in that each lost-motion mechanism (23, 24; 36, 37) has an individually adjustable end position (25, 26) for the lost stroke on its foot end side.

6. Adjustable bed according to one or more of the preceding claims, characterized in that the operating rod (13) is arranged, for a translatory movement and the lost-motion mechanism is a pin (23, 36) and slot (24, 37) device, and that the drive device comprises a threaded spindle and nut mechanism (15), so that the prime-mover (16) is of a rotary type.

Drawing