JPH07187587A - Pantographic elevating device - Google Patents

Abstract

PURPOSE:To enable initial low-speed rising operation of a pantograph by using a simple mechanism so as to decrease load at the time of starting by performing the initial rising operation by a cam mechanism, and subsequently raising a pantograph by an actuator. CONSTITUTION:A screw shaft 2 is rotated by a driving motor 1 to move a cam driving part 3 and a supporting point driving part 4 in the direction of a movable supporting point 8. By the movement of the cam driving part 3, a roller 7 of a wedge type cam 6 is brought into contact with the part 3 to push up an arm member along the angle of inclination of the cam 6. When the cam driving part 3 and the supporting point driving part 4 are further moved in the direction of the movable supporting point 8, the supporting point driving part 4 is joined to the movable supporting point 8 so that the movable supporting point 8 is moved toward a fixed supporting point 9 by the supporting point driving part 4, thereby further raising a pantograph.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pantograph type lifting device for lifting and lowering an article or a person by means of a pantograph.

[0002]

2. Description of the Related Art A pantograph type lifting device is shown in FIG.
By adjusting the distance between the movable support points 8 and the fixed support points 9 of the arm members 5 that intersect to form a link as shown in FIG.
The platform 10 is moved up and down. There is also a drive mechanism in which a hydraulic cylinder is used instead of the screw shaft 2. Such a pantograph type elevating device has an advantage that the elevating operation can be performed only by adjusting the support point interval and the mechanism is simple. On the other hand, the above-described pantograph-type lifting device has a problem that a large force is required at the supporting point at the time of starting and the load on the driving unit is large. An apparatus for solving this problem is disclosed in Japanese Patent Laid-Open No. 58-125584.
No. 1 proposes a pantograph type elevator that reduces the load at the start of the vantagraph by installing a spring at the descending point of the pantograph and configuring the spring to contract at the lowest point. .

[0003]

Recently, there has been a strong demand for the pantograph-type lifting device to ensure safety for workers and related persons. for that reason,
Not only additional equipment such as a buzzer and a warning light to notify the start-up but also an operation of raising the pantograph at a low speed at the initial rise and then raising it at a predetermined speed is required in order to warn the start of the lift.

The above-mentioned pantograph type lifting device of Japanese Patent Laid-Open No. 58-125584 is preferable because it can reduce the load at the time of starting, but it does not have a mechanism for performing the initial low speed rising operation of the pantograph. An object of the present invention is to provide a pantograph type lifting device capable of performing an initial low speed rising operation of a pantograph with a simple mechanism and reducing a load on a drive device at the time of starting.

[0005]

The present inventor has found that by performing the initial raising operation of the pantograph by the cam mechanism, it is possible to simultaneously perform the initial low speed raising operation and the reduction of the load at the time of starting. Arrived That is, according to the present invention, a cam mechanism that pushes up an arm member that constitutes a link to perform an initial raising operation of the pantograph, and moves one support point of the pantograph toward the other support point of the pantograph following the initial rise. It is a pantograph type lifting device characterized by comprising an actuator for raising.

The cam mechanism of the present invention can raise the pantograph by the cooperation of the cam and the roller. Further, if the actuator of the present invention is provided with a cam drive unit of the cam mechanism and a support point drive unit that is coupled to one of the support points of the pantograph after the initial raising operation and moves the support point toward the other support point, It is preferable because the mechanism can be simplified. One support point and the other support point in the present invention are
They may be movable with respect to each other, or one may be fixed and the other may be movable. If a screw is used as the actuator, positioning can be performed with higher accuracy than in a hydraulic cylinder, which is preferable.

[0007]

One of the greatest features of the present invention is that the cam mechanism performs the initial raising operation. In the cam mechanism, for example, if the arm member forming the link is provided with the cam, the arm member can be pushed up along the cam shape. Therefore, it is possible to change the initial rising speed of the pantograph by changing the inclination of the cam. Further, by adjusting the inclination of the cam, an appropriate load can be applied to the cam drive unit, and the load at the start of the pantograph can be reduced.

The cam drive unit of the present invention may be one in which the cam is fixed to the arm member of the pantograph and the arm member is pushed up by moving a sliding member such as a roller that cooperates with the cam. Conversely, a sliding member such as a roller contacting the cam may be fixed to the arm member of the pantograph and the cam may be moved.

The present invention further comprises an actuator for moving the one support point of the pantograph toward the other support point to raise the pantograph subsequent to the initial raising operation by the cam mechanism. This is because it is impractical to perform all the pantograph raising operations by the cam mechanism because the cam becomes huge. In addition, the use of a huge cam in a pantograph type lifting device that can be moved up and down simply by adjusting the distance between the support points impairs the advantage of its original small size and simple structure. Not preferable. Therefore, in the present invention, it is necessary that the ascending operation following the initial ascending is performed by the actuator that narrows the support points.

Further, as the actuator of the present invention, a cam drive portion of the cam mechanism and a support point drive portion which is connected to one of the support points of the pantograph after the initial ascending operation and moves the support point toward the other support point. If the actuators are provided side by side, the same actuator can perform the initial ascending by the cam mechanism and the subsequent movement of the support point, and the simplification of the mechanism can be achieved.

If a screw is used as the actuator, the positioning can be performed with higher accuracy as compared with a hydraulic cylinder, and the angle of the screw can be adjusted so as not to descend due to the load of the pantograph. It will be safe because it can be stopped on the spot even if it is disconnected. If the screw is moved by an electric motor, it can be operated safely at a place away from the lifting device by a cord or the like. Power can be transmitted even more efficiently by moving the screw with a ball screw.

[0012]

FIG. 1 shows an example of a pantograph type lifting device according to the present invention. A screw shaft 2 serving as an actuator is connected to the drive motor 1 shown in FIG. 1, and a cam drive unit 3 and a support point drive unit that move on the screw shaft 2 by the rotation of the drive motor 1 are connected to the screw shaft 2. 4 are installed. Further, a wedge-shaped cam 6 is installed on the arm member 5 forming the link, and the roller 7 provided in the cam drive unit 3 is configured to come into contact with the cam surface.

An example of the operation of the pantograph type lifting device of the present invention will be described below with reference to FIGS. 1 and 2. From the lowest position of the pantograph lifting and lowering device shown in FIG. 1, the screw shaft 2 is rotated by the drive motor 1 to move the cam drive unit 3 and the support point drive unit 4 in the direction of the movable support point 8. As shown in FIG. 2A, the movement of the cam drive unit 3 causes the wedge-shaped cam 6 and the roller 7 to come into contact with each other to push up the arm member along the inclination angle provided on the cam 6. When the cam drive unit 3 and the support point drive unit 4 are further moved in the direction of the movable support point 8, the support point drive unit 4 joins with the movable support point 8, and the support point drive unit 4 moves the movable support point 8 to the fixed support point. The pantograph can be moved further towards 9, as shown in FIG.

By rotating the screw shaft 2 shown in FIG. 1 in the opposite direction, the descending operation can be performed by performing the above-described ascending operation and the opposite operation. FIG. 3 shows another example of the cam mechanism of the present invention. The cam mechanism of FIG. 3 is similar to that of FIG.
The positions of the roller 7 and the cam 6 of the cam mechanism 3 shown in FIG. According to the cam mechanism 3 of FIG. 3, by moving the cam 6, the pantograph can be initially moved upward.

[0015]

According to the present invention, by performing the initial raising operation by the cam mechanism, the initial low speed raising operation of the pantograph can be performed by using a simple mechanism, and the load at the time of starting can be reduced. Therefore, it is extremely effective for the safety and downsizing of the pantograph lifting device.

[Brief description of drawings]

FIG. 1 is a front view showing an example of a pantograph type lifting device of the present invention.

FIG. 2 is a diagram for explaining a raising operation of the pantograph type lifting device of the present invention.

FIG. 3 is a view showing another example of a cam mechanism relating to the pantograph type lifting device of the present invention.

FIG. 4 is a diagram showing an example of a conventional pantograph-type lifting device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 drive motor, 2 screw shaft, 3 cam drive part, 4 support point drive part, 5 arm members, 6 cam, 7 roller, 8 movable support point, 9 fixed support point, 10 cargo bed

Claims (4)

[Claims] 1. A cam mechanism for pushing up an arm member constituting a link to perform an initial raising operation of a pantograph; and, following the initial raising, one support point of the pantograph is moved toward the other support point of the pantograph. A pantograph-type lifting device, comprising an actuator for raising. 2. The pantograph type lifting device according to claim 1, wherein the cam mechanism raises the pantograph by the cooperation of the cam and the roller. 3. The actuator includes a cam drive unit of a cam mechanism, and a support point drive unit that is connected to one of the support points of the pantograph after the initial ascending operation and moves the support point toward the other support point. The pantograph lifting device according to claim 1 or 2, which is installed. 4. The actuator according to claim 1, wherein the actuator is movable by a screw.
The pantograph type lifting device according to any one of 1.