JP2616650B2 - Lifting bed - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an elevating bed used for an X-ray fluoroscopic apparatus, an X-ray CT apparatus, and the like.

[0002]

2. Description of the Related Art FIG.
This will be described with reference to FIG. FIG. 9 shows a configuration of an elevating bed that raises and lowers a bed frame with respect to a base using a rack and a pinion.

[0003] In this elevating bed, a movable frame 4 supported by rollers 3a to 3d and loosely inserted in a vertically movable manner is attached to a bed frame 5, and a motor 6
In this configuration, a rack 9 meshing with a pinion 8 rotated via a gear box 7 is attached to the movable frame 4. By rotating the motor 6, the movable frame 4 attached with the rack 9 meshing with the pinion 8 is moved up and down with respect to the column 2, so that the bed frame 5 is moved up and down in parallel with the base 1. Also, the bed frame 5 includes
A top plate (not shown) that supports the subject is supported.

However, in the case of the elevating bed using the rack and the pinion, there are the following problems. That is, in order to stably support the movable frame 4, it is necessary to increase the distance between the rollers 3 a and 3 b and between the rollers 3 c and 3 d, and if so, the columns 2 must be correspondingly elongated. If the column 2 is lengthened, the bed frame 5 cannot be lowered to a position where the subject can easily get on and off.

[0005] To cope with this, an elevating bed is generally used in which the bed frame and the base are connected by an X-link mechanism, and the X-link mechanism is bent up and down to raise and lower the bed frame in parallel to the base. This configuration will be described with reference to FIG.

In the figure, reference numeral 11 denotes an X-link mechanism, and the X-link mechanism 11 is constructed by pivotally connecting a first link 11a and a second link 11b at a fulcrum a. The first link 11a has a distal end pivotally connected to the bed frame 5 at a fulcrum b, and a base end slidably supported by the base 1. On the other hand, the second link 11b has a distal end slidably supported by the bed frame 5 and a base end pivotally connected to the base 1 at a fulcrum c. The distal end of a screw shaft 13 screwed to a jack 12 fixed to the base 1 is connected to the base end of the first link 11a.

The configuration of the jack 12 is shown in FIG. A worm wheel 16 screwed to a worm shaft 15 rotated by a motor 14 (see FIG. 10) is housed in a case 18 sandwiched between roller bearings 17a and 17b, and is screwed into a screw hole 16a cut into the worm wheel 16. The screw shaft 13 is screwed.

When the motor 14 is rotated, the worm wheel 16 is rotated in the case 18 and the screw shaft 13 pushes or pulls the base end of the first link 11a, so that the X link mechanism 11 is bent up and down. The bed frame 5 is moved up and down in parallel with the base 1.

[0009]

However, the prior art having such a structure has the following problems. That is, in the configuration of the conventional example, the driving force required to raise the bed frame 5 differs depending on the height of the bed frame 5.

This will be described with reference to FIGS. As shown in FIG. 12, when the load applied to the X-link mechanism 11 (the bed frame 5, the top plate, the subject lying on the top plate, and the like) is P, the first link 11a and the second link 1 having a length L are provided.
A load of (P / 2Sin (θ)) is applied to 1b. Here, θ is the angle of the base 1, the first link 11a, and the second link 11b at the height H of the bed frame 5. In order to push the base end of the first link 11a in opposition to this, ((P / 2Sin (θ)) ×
Cos (θ)) = (P × Cot (θ) / 2) driving force F
Is required. Here, when a numerical value is substituted for θ, as shown in FIG. 13, when the position of the bed frame 5 is in a low state, the mechanical efficiency (P / F) is poor, so a large driving force F is required. Yes, as the position of the bed frame 5 increases, the mechanical efficiency increases and the driving force F decreases.

Therefore, when the bed frame 5 is raised with the bed frame 5 raised and the driving force is raised, the extra driving force is given to the X-link mechanism 11 as the bed frame 5 is raised. Energy efficiency is low.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide an elevating bed with improved energy efficiency of elevating and lowering a bed frame.

[0013]

The present invention has the following configuration to achieve the above object. That is, according to the present invention, the bed frame supporting the table top for supporting the subject and the base are connected by an X-link mechanism, and a driving unit for vertically bending and extending the X-link mechanism is driven to connect the bed frame to the base. In the elevating bed configured to be raised and lowered in parallel to the, when the bed frame is at the lowermost position, in a state where the compression coil spring is compressed, and when raising the bed frame from the lowermost position,
The compression coil spring is incorporated into the drive unit so that a restoring force of the compressed compression coil spring is applied to a drive force of the drive unit for vertically bending and extending the X-link mechanism, and the drive unit operates as the compression coil spring. A compression coil spring having a non-linear characteristic for making the driving force of the section substantially constant is used.

[0014]

The operation of the present invention is as follows. A compression coil spring having a non-linear characteristic is provided to a drive unit for vertically bending and extending the X-link mechanism. The X-link is provided by the drive unit when the bed frame is raised from the lowest position in a compressed state when the bed frame is at the lowest position. The structure incorporates the restoring force of the compressed coil spring with the compressed nonlinear characteristic to the driving force for bending and stretching the mechanism, so the nonlinear characteristic that assists the driving force when the largest driving force is required The restoring force of the compression coil spring is the largest, and the driving force of the drive unit decreases as the position of the bed frame increases, and the restoring force of the compression coil spring having the non-linear characteristic also decreases according to the change. Therefore, the driving force of the driving unit can be assisted by the restoring force of the compression coil spring having the non-linear characteristic in accordance with the change in the driving force required to bend the X-link mechanism up and down. It can be constant, and the energy efficiency of the drive unit can be improved.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As described above, the present invention is characterized in that a compression coil spring having a non-linear characteristic is incorporated in a driving portion of an X-link mechanism. An example in which a coil spring is incorporated will be described. FIG. 1 is a front view showing a configuration of an elevating bed in which a compression coil spring having a linear characteristic is incorporated in a driving section of an X-link mechanism. In this example, as in the conventional example, an elevating bed using a screw shaft and a jack as a driving unit for vertically bending and extending the X-link mechanism will be described as an example. In the figure, portions denoted by the same reference numerals as those of the conventional example are the same as those of the conventional example, and thus detailed description thereof will be omitted.

In this example, as shown in FIG.
A compression coil spring 10 having a linear characteristic is fitted between the base end portion 3 and the jack 12. To explain the configuration in detail,
A spring receiving member 21 is attached to the base end of the screw shaft 13, and two end members of the compression coil spring 20 are fixed to the screw shaft 13 between the spring receiving member 21 and the jack 12. 22a and 22b are fitted.
As shown in FIG. 2, the guide members 22 a and 22 b maintain the center axis of the compression coil spring 20 in substantially the same positional relationship with respect to the screw shaft 13 and guide movement along the screw shaft 13. Things. In this example, as the compression coil spring 20, a cylindrical type having an equal pitch is used.

Next, the operation of the example using the compression coil spring having the above-mentioned linear characteristic will be described with reference to FIGS. FIG.
(A) shows that the bed frame 4 is at the lowest position, that is, the base 1
Angle between the first link 11a and the second link 11b is 1
FIG. 3 is a view showing a state of the compression coil spring 20 when the compression coil spring 20 is at 5 ° (the height H of the bed frame 5 is 0.26 L, where L is the length of the first link 11 a and the second link 11 b).
(B) is θ = 20 ° (height H of bed frame 5 = 0.34)
FIG. 3C shows the state of the compression coil spring 20 when the bed frame 5 is raised to L). FIG. 3C shows the state where the bed frame 5 is at the highest position (θ = 35 °, the height of the bed frame 5 is H = 0. 57L)
FIG. 4 is a diagram showing a state of the compression coil spring 20 when the compression coil spring 20 is in the state shown in FIG. 4 shows the height H of the bed frame 5 when the bed frame 5 is raised as shown in FIG. 3, the required driving force F required to raise the bed frame 5 (solid line), and the restoration of the compression coil spring 20. FIG. 3 is a graph showing a relationship between a force Fb (dashed line) and a driving force Fm (dotted line) of a motor 14.

When the bed frame 5 is at the lowest position,
As shown in (a), the screw receiving member 21 is connected to the jack 12.
, And the compression coil spring 20 is in the most compressed state. At this time (H = 0.26L), the restoring force Fb of the compression coil spring 20 is the largest as shown by the one-dot chain line in FIG. 4, and as shown by the solid line in FIG.
The required driving force F is the largest.

Next, as the bed frame 5 is raised,
As shown in FIGS. 3A and 3B, the screw receiving member 2
1 gradually moves away from the jack 12, and the compression coil spring 20 expands. At this time (H = 0.26L
.About.H = 0.34 L), the restoring force Fb of the compression coil spring 20 decreases constantly as shown by the dashed line in FIG. 4, and the required driving force F gradually decreases as shown by the solid line in FIG. Become smaller.

Further, as the bed frame 5 is raised to the highest position, as shown in FIGS. 3 (b) and 3 (c),
The screw receiving member 21 moves further away from the jack 12, and the compression coil spring 20 approaches a steady state.
At this time (H = 0.34L to H = 0.57L), as shown by the one-dot chain line in FIG.
b approaches “0”, and as shown by the solid line in FIG.
The required driving force F is further reduced.

Then, when the bed frame 5 is raised to the highest position, the screw receiving member 21 is located farthest from the jack 12 as shown in FIG. 3C, and the compression coil spring 20 is in a steady state. At this time (H = 0.57
L), as shown by the dashed line in FIG.
The restoring force Fb of 0 becomes “0”, and the required driving force F also becomes the minimum as shown by the solid line in FIG.

In the raising operation of the bed frame 4 described above,
The required driving force F is obtained by adding the restoring force Fb of the compression coil spring 20 to the driving force of the motor 14. Therefore, if the restoring force Fb of the compression coil spring 20 is subtracted from the required driving force F, the driving force Fm of the motor 14 in the above configuration can be calculated backward. When this is shown in a graph, it becomes as shown by the dotted line in FIG. That is, the range of change between the maximum value and the minimum value of the driving force Fm of the motor 14 can be reduced.
Can have better energy efficiency than before.

Next, a first embodiment of the present invention will be described with reference to FIGS.
This will be described with reference to FIG. In the above-described example, the compression coil spring is configured to use a cylindrical compression coil spring having an equal pitch. However, in the first embodiment of the present invention, as a compression coil spring having a non-linear characteristic, as shown in FIG. A conical compression coil spring 30 is used. The other configuration is the same as the previous example using the compression coil spring having a linear characteristic, and thus the description is omitted here.

The restoring force Fb of the conical compression coil spring 30
Has a non-linear characteristic similarly to the required driving force when the bed frame 5 is raised. Therefore, when the bed frame 5 is raised in the configuration of FIG. 5, as shown in FIG. 6, a conical compression coil spring 30 that can keep the driving force Fm of the motor 14 constant can be designed. By raising the bed frame 5 using the conical compression coil spring 30, energy efficiency can be further improved.

Next, a second embodiment will be described with reference to FIG. In the second embodiment, as shown in FIG. 7, a compression coil spring 40 having an unequal pitch is used as a compression coil spring having a non-linear characteristic.

The restoring force Fb of the unequal pitch spring 40 also has a non-linear characteristic like the restoring force Fb of the conical compression coil spring 30. Therefore, even with the unequal-pitch compression coil springs 40, as shown in FIG. 6, it is possible to design the unequal-pitch compression coil springs 40 to keep the driving force Fm of the motor 14 constant. The energy efficiency can be further improved by raising the bed frame 5 using the compression coil springs 40 having the pitch.

In each of the above-described embodiments, an elevating bed using a screw shaft and a jack has been described as an example of a drive unit for vertically bending and extending the X-link mechanism. The same applies to an elevating bed that allows the X-link mechanism to bend up and down by expanding and contracting a rod 51 of an air cylinder 50, as shown in FIG.

[0028]

As is apparent from the above description, according to the present invention, a compression coil spring having a non-linear characteristic is provided in the drive unit for vertically bending and extending the X-link mechanism, and the compression coil spring is compressed when the bed frame is at the lowest position. When the bed frame is raised from the lowermost position, the driving force for vertically bending and extending the X-link mechanism by the driving unit is incorporated so that the restoring force of the compressed non-linear characteristic compression coil spring is applied. Therefore, when the largest driving force is required, the restoring force of the non-linear compression coil spring that assists the driving force is the largest, and the driving force of the driving unit decreases as the position of the bed frame increases. Accordingly, the restoring force of the compression coil spring having the non-linear characteristic also decreases. Therefore, the restoring force of the compression coil spring having a non-linear characteristic can be assisted in the driving force of the driving unit in accordance with the change in the driving force required to bend the X-link mechanism up and down. It can be constant, and the energy efficiency of the drive unit can be improved.

[Brief description of the drawings]

FIG. 1 is a front view showing a configuration example of an elevating bed using a compression coil spring having a linear characteristic.

FIG. 2 is a sectional view showing a configuration of a main part of the device shown in FIG.

FIG. 3 is a diagram showing the operation of the device shown in FIG.

4 shows the height of the bed frame and the required driving force required for raising the bed frame when the bed frame is raised by the apparatus shown in FIG. 1;
FIG. 4 is a graph showing a relationship between a restoring force of a compression coil spring and a driving force of a motor.

FIG. 5 is a diagram showing a configuration of a main part of the device of the first embodiment of the present invention.

FIG. 6 is a graph showing the relationship between the height of the bed frame and the required driving force required for raising the bed frame, the restoring force of the compression coil spring, and the driving force of the motor when the bed frame is raised by the apparatus of the first embodiment. It is.

FIG. 7 is a diagram showing a configuration of a main part of the device of the second embodiment.

FIG. 8 is a diagram showing a configuration of a modified example.

FIG. 9 is a diagram showing a configuration of a first conventional example.

FIG. 10 is a diagram showing a configuration of a second conventional example.

FIG. 11 is a sectional view showing a configuration of a jack.

FIG. 12 is a diagram for explaining a problem of a conventional example.

FIG. 13 is a diagram for explaining a problem of the conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Base 5 ... Bed frame 11 ... X-link mechanism 11a ... First link 11b ... Second link 12 ... Jack 13 ... Screw shaft 14 ... Motor 20, 30, 40 ... Compression coil spring 21 ... Spring receiving member 22a, 22b ... Guide Member 50: Air cylinder 51: Rod of the air cylinder F: Driving force for raising the bed frame Fb: Restoring force of the compression coil spring Fm: Driving force of the motor

Claims (1)

(57) [Claims] An X-link mechanism connects a bed frame that supports a tabletop on which a subject is supine to a base with an X-link mechanism, and drives a drive unit that causes the X-link mechanism to bend up and down to drive the bed frame to the base. In the elevating bed configured to be raised and lowered in parallel to the bed frame, when the bed frame is at the lowest position, in a state where the compression coil spring is compressed,
And, when raising the bed frame from the lowermost position, the compression coil spring is adjusted so that a restoring force of the compressed compression coil spring is applied to a driving force of the drive unit for vertically bending and extending the X-link mechanism. A lifting bed which is incorporated in a drive unit and uses a compression coil spring having a non-linear characteristic for making the driving force of the drive unit substantially constant as the compression coil spring.