JPH0444546B2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention is applicable to, for example, CT (Computer Tomography).
Regarding a table lifting device for lifting and lowering a table, more specifically, it includes a spindle rotationally driven by a motor, a cylinder having a nut screwed into a threaded portion of the spindle and moving in the axial direction by rotation of the spindle, a guide provided to inhibit relative displacement in the axial direction with the spindle and guide the cylinder in the axial direction;
The present invention relates to a table lifting device that raises and lowers the table by locking one of the cylinder or the guide to the table side and locking the other to the fixed side.

(Prior Art) As this type of elevating device, those shown in FIGS. 2 and 3 are known. Here, Figure 2 shows CT
FIG. 3 shows a cross-sectional view of the lifting device for the table. In these figures, 1 is a fixed frame installed on the floor, 2 is an elevating table, and the fixed frame 1 and elevating table 2 have arms 3 and 4 of the same length connected to pins 5, 6,
The fixed frame 1, the lifting table 2, and the arms 3 and 4 form a parallel crank mechanism. 9 is a motor, which is installed on the gear case 10, and the output shaft 9a is connected to the gear case 10.
The gear 11a in the inner gear train 11 is fitted into the gear 11a. The lower end of the spindle 12 is fitted into the shaft hole of the final gear 11b of the gear train 11 so as to rotate together with the final gear 11b. Also, Natsu 1
3 is screwed into the threaded portion of the spindle 12 and fixed to the lower end of the lifting cylinder 14. A guide 15 that guides the movement of the lifting cylinder 14 in the axial direction of the spindle 12 is provided around the lifting cylinder 14 and is integrally constructed with the gear case 10.
A thrust bearing 16 is inserted above the final gear 11b and fixed by a retaining ring 17 and a stopper 18 so that the spindle 12 rotates smoothly in a fixed position.

A potentiometer 19 that detects the height of the lifting table is installed on the gear case 6, and is connected to the gear train 1.
Potentiometer 19 to the shaft hole of No. 1 gear 11c
The input shaft is inserted. The elevating device is pivotally attached to the fixed frame 1 and the elevating table 2 by pins 20 on the fixed frame side and pins 21 on the elevating table side.

The conventional CT table lifting device is configured as described above, and when the motor 9 is rotated, the rotation of the motor 9 is inserted into the shaft hole of the final gear 11b via the gear train 11 in the gear case 10. The power is transmitted to the spindle 12 located there. Lifting cylinder 1 having a nut 13 screwed into a threaded portion of a spindle 12
4, the guide 15 is rotated by the rotation of the spindle 12.
, the spindle 12 is moved in the axial direction. The fixed frame 1, the lifting table 2, and the arms 3 and 4 form a parallel flank mechanism, and the lifting cylinder 14 is pivotally connected to the lifting table 2 by a pin 21, and the gear case 10 is pivotally connected to the fixed frame 1 by a pin 20. , by the movement of the lifting cylinder 14,
The lifting table 2 moves parallel to the fixed frame 1.

(Problems to be Solved by the Invention) In the conventional CT table lifting device as described above, when lifting the lifting table 2, the load of the patient and the lifting table 2 is applied to the threaded joint between the spindle 12 and the nut 13. Therefore, a very large torque is required to be applied to the spindle 12. Lowering the lifting table 2 requires less torque than raising it due to the gravity of the lifting table and the patient, but with conventional CT table lifting devices,
A motor 9 with a capacity of about 100 to 150 W is required, which poses problems such as increased cost of the motor, hindrance to miniaturization, and high noise.

The present invention has been made in view of these points,
The purpose is to obtain a table lifting device that is compact, has low noise, and is cost-reduced because the motor has a low capacity.

(Means for Solving the Problems) The present invention for solving the above problems includes a cylinder driven in the axial direction and a guide for guiding the cylinder, and one of the cylinder or the guide is moved toward the table side. and lock the other side to the fixed side,
In the table lifting device for lifting and lowering the table, a compression coil spring is fitted around the cylinder and the guide coaxially with the cylinder and the guide so that the cylinder and the guide receive a repulsive force. It is characterized by:

(Function) In the table elevating device of the present invention, a compression coil spring is fitted into the elevating cylinder and the guide, and the cylinder and the guide receive repulsive force to constantly push up the elevating table. Therefore, the load applied to the threaded portion of the spindle and the nut is reduced, the torque applied to the spindle when raising or lowering the lifting table is also reduced, and the motor capacity is also reduced. In addition, since the compression coil spring is arranged coaxially around the cylinder, during assembly, for example, after passing the coil spring through the cylinder (and guide), the lifting table can be fixed to the tip of the cylinder. It's easy. Also, after assembly,
It has a compact configuration that does not take up much space. moreover,
The coil is dynamically stable against the movement of the lifting table, effectively reducing various stresses applied to the cylinder.

(Embodiment) FIG. 1 is a sectional view showing an embodiment of the present invention, and numerals 1 to 21 are completely the same as the conventional device described above. In this figure, 22 is the lifting cylinder 14
The present invention is characterized in that the compression coil spring 22 is fitted into the guide 15. In this case, it is desirable that the compression coil spring 22 always have a repulsive force at least equal to the load of the lifting table 2 at each height. In the table lifting device for a CT table configured as described above, the lifting cylinder 14 and the guide 15 receive a repulsive force, so that the lifting table 2 is constantly pushed up. Therefore, the load applied to the threaded joint between the spindle 12 and the nut 13 is reduced compared to the case without the compression coil spring 22, and when the lifting table 2 is raised or lowered, the torque applied to the spindle 12 is also reduced by the compression coil spring 22.
decreases compared to the case without. Therefore, the capacity of the motor 9 can be reduced compared to the case without the compression coil spring 22, and may be about 60W.
In addition, the CT table has a parallel crank mechanism, and the lower the position of the lifting table 2 is, the more the lifting cylinder 14 is in a sleeping state, and the force of the lifting cylinder 14 to raise or lower the lifting table 2 is A larger force is required due to an increase in the horizontal component force that does not contribute to lifting up and a decrease in the vertical component force that pushes up the lifting table 2. In this case, the length of the lifting cylinder 14 is also shortened, and the compression length of the compression coil spring 22 is reduced. Since the repulsion force also increases, the load applied to the threaded joint between the spindle 12 and the nut 13 when lifting the lifting table 2 is reduced to some extent, which is advantageous.

Note that the present invention is not limited to the above embodiments, and various modifications are possible. For example, a rod may be used instead of the lifting cylinder. Also, similar effects can be expected by using an air or hydraulic cylinder instead of the lifting cylinder driven by rotation of a motor.

(Effects of the Invention) As explained above, with the simple structure of inserting a compression coil spring into the lifting cylinder and guide, the lifting cylinder and guide receive repulsive force and constantly push up the lifting table, allowing the spindle and nut to By reducing the load on the threaded part, the load on the motor can be reduced, and the motor capacity can be made smaller than conventional devices. Also, by arranging the compression coil spring coaxially with the cylinder, it is compact, has low noise, A table lifting device that reduces costs can be obtained.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing one embodiment of the present invention, and FIG.
The figure is a side view of a conventional CT table, and FIG. 3 is a sectional view of a conventional CT table lifting device. 1...Fixed frame, 2...Elevating table,
3, 4... Arm, 5, 6, 7, 8... Pin, 9
... Motor, 10 ... Gear case, 11 ... Gear train, 11a, 11b, 11c ... Gear, 12 ...
Spindle, 13... Nut, 14... Lifting cylinder, 15... Guide, 16... Thrust bearing,
17... Retaining ring, 18... Stopper, 19... Potentiometer, 20, 21... Pin, 22...
Compression coil spring.

Claims (1)

[Claims] 1. Equipped with a cylinder driven in the axial direction and a guide that guides the cylinder, one of the cylinder or the guide is locked to the table side, and the other is locked to the fixed side, so that the table can be raised and lowered. A compression coil spring is provided around the cylinder and the guide so that the cylinder and the guide receive a repulsive force.
A table lifting device characterized in that the table lifting device is fitted coaxially with the cylinder and guide.