JPH0642524Y2 - Bed back lifting mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a bed lifting mechanism.

(Prior Art) As a bed raising mechanism, a push-up arm is provided below a back floor plate rotatably supported by a bed frame, and a tip end of the push-up arm is driven by a screw shaft type. There is one in which the back floor plate is pivotally raised by moving it by means of a moving member of a telescopic rod. Conventionally, the tip end portion of the push-up arm is configured to be directly moved by the moving member of the screw shaft type telescopic rod.

(Problems to be solved by the invention) In the above configuration, the required force for moving the push-up arm is
As shown by the broken line in FIG. 3, it gradually increases as the back floor plate rotates. Therefore, the crank handle can be driven with a light force while the rotation angle of the back floor plate is small, but the required force gradually increases as the rotation angle increases, and the crank handle becomes heavy.

The present invention aims to solve such problems.

(Means for Solving the Problems) The structure of the present invention for solving the above problems will be described with reference to the drawings showing an embodiment. The present invention is rotatably supported on a bed frame 1. A push-up arm 3 is provided below the back floor plate 2, and a tip portion 4 of the push-up arm 3 is moved by a moving member 6 of a screw shaft type expansion / contraction rod 5 so that the back floor plate 2 is rotated and raised. In the mechanism, an eccentric sprocket in which a drive chain 7 is interposed between the moving member 6 of the telescopic rod 5 and the tip 4 of the push-up arm 3 and the drive chain 7 is supported by the bed frame 1 The eccentric sprocket 8 is configured to change the direction by means of the driving chain 7. The ratio between the back floor It is configured such that the plate 2 gradually increases as the plate 2 rises.

In the above configuration, the screw shaft type telescopic rod 5 may be driven by the crank handle 9 or may be driven by an electric motor.

Further, the drive chain 8 is formed over the entire space between the moving member 6 of the telescopic rod 5 and the tip end portion 4 of the push-up arm 3, and is formed only at the corresponding portion of the eccentric sprocket 8 It can also be composed of a drive wire.

(Operation and Embodiment) The operation of the present invention will be described with reference to the drawings showing the embodiment.

When the crank handle 9 is rotated and one end of the drive chain 7 is moved rightward in the figure by the moving member 6 of the screw shaft type telescopic rod 5, the drive chain 7 is changed in direction by the eccentric sprocket 8. , The tip portion 4 of the push-up arm 3 is moved to the left side in the drawing from the other end side. Therefore, due to the movement of the push-up arm 3, the back floor plate 2 moves around the fulcrum 10,
It rotates clockwise and rises. On the other hand, the eccentric sprocket 8 rotates as the drive chain 7 moves, and this rotation causes the distance A between the action point on the push-up arm 3 side and the rotation axis.
, The value of the ratio of the distance B between the point of action on the telescopic rod 5 side and the rotation axis, that is, the distance B / distance A gradually increases.

As described above, the required force for directly moving the push-up arm 3 gradually increases as shown by the broken line in FIG. 3, but in the present invention, at the same time, the eccentric sprocket 8 is used. The value of the ratio and the distance B / distance A in the direction change of the drive chain 7 due to are gradually increased as the back floor plate 2 is raised, as shown by the two-dot chain line in FIG. The increase in power can be offset. In this way, the force required to move the push-up arm 3 by the moving member 6 of the screw shaft type telescopic rod 5 via the drive chain 7 to rotate and raise the back floor plate 2 is increased as shown by the solid line in FIG. It can be averaged over a range of motion.

In the illustrated embodiment, the value of the ratio, distance B / distance A
Is such that the back floor plate 2 is the smallest in the horizontal state and the back floor plate 2 is the largest in the maximum inclined state, that is, the eccentric sprocket 8 rotates half a turn in the rotation range of the back floor plate 2. However, the rotation of the eccentric sprocket 8 within a half circumference can be made to correspond to the rotation range, and the fulcrum 10 and the tip 4 of the push-up arm 3 have the positional relationship shown in the drawing. Can correspond to the state where the back floor plate 2 is slightly rotated, with the portion having the minimum ratio value.

(Effect of the Invention) As described above, the present invention can average the force required to rotate and raise the back floor plate by the moving member of the screw shaft type expansion / contraction rod over the rotation range. When the telescopic rod is driven by the crank handle, the operating force is averaged to prevent the inconvenience that the crank handle becomes heavier as the turning angle increases, and the telescopic rod is driven. The maximum required torque can be reduced even when using an electric motor,
Since a small capacity can be used, there is an effect that the cost can be reduced.

[Brief description of drawings]

FIG. 1 is an explanatory side view showing the overall configuration of the embodiment, FIGS. 2 (a) and 2 (b) are enlarged explanatory side views showing the configuration and operation of the main part, and FIG. It is explanatory drawing showing the required force in a device. Reference numeral 1 ... Bed frame, 2 ... Back floor plate, 3 ... Push-up arm, 4 ... Tip part, 5 ... Screw shaft type telescopic rod, 6
...... Movement member, 7 ... Drive chain, 8 ... Eccentric sprocket, 9 ... Crank handle, 10 ... fulcrum.

Claims (3)

[Scope of utility model registration request] 1. A push-up arm is provided below a back floor plate rotatably supported by a bed frame, and a tip end portion of the push-up arm is moved by a moving member of a screw shaft type telescopic rod to rotate the back floor plate. An eccentric sprocket in which a drive chain is interposed between a moving member of the telescopic rod and a tip end portion of the push-up arm in a bed raising mechanism for dynamically raising the bed, and the drive chain is supported by the bed frame. The eccentric sprocket has a structure in which the ratio of the distance between the action point on the telescopic rod side and the rotation axis to the distance between the action point on the push-up arm side and the rotation axis by the drive chain is:
Bed back-raising mechanism configured to gradually increase as the back floor plate rises 2. The bed lifting mechanism according to claim 1, wherein the screw shaft type telescopic rod is configured to be driven by a crank handle. 3. The drive chain is configured only between the movable member of the telescopic rod and the tip end portion of the push-up arm at a corresponding position of the eccentric sprocket, and the other is constituted by a drive wire. Bed back lifting mechanism