JPH0532318B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a lifting device used for a transport vehicle, an electric wheelchair, etc., and particularly to a spring type balancer device thereof.

<Conventional technology> As a conventional technology, for example, 6 journals of Biomechanism (edited by the Biomechanism Society, published by the University of Tokyo Press)
There is one shown on page 173, FIG. 1a.

This prior art is a lifting device in which an X-shaped link is driven by an electric spiral mechanism or a hydraulic cylinder.

In the conventional elevating device as described above, the upper and lower ends of one of the X-shaped links 1 and 2 are rotatably fixed to one end of the base 3 and the elevating seat plate 4, as shown in FIG. The other upper and lower ends of the links 1 and 2 are slidably supported by movable supports 5 and 6 relative to the other ends of the base 3 and seat plate 4, respectively.

<Problems to be Solved by the Invention> In the case of the conventional lifting device as described above, when a load W is applied to the lifting seat plate 4, it must be applied to the moving fulcrum 5 of the X-shaped link in order to maintain balance. Force F
is expressed by the following formula.

F=W×cot θ (However, losses due to friction etc. are ignored.) In other words, when the angle θ → o, in other words, when the elevator seat plate 4 is low, the force F required to maintain balance is infinite. Get closer to the big one.

Therefore, when trying to make the lifting device capable of handling from low to high positions and downsizing the entire device, the actuator 7 such as an electric motor
There was a problem in that the energy sources such as batteries were also becoming larger.

In addition, in order to solve the above problem, an arrangement has been devised in which a tension type coil spring 9 is incorporated in the portion of the X-shaped link below the intermediate connection point 8, as shown in FIG. Since the fulcrum movement of the type link is large when lifting and lowering, if the coil spring 9 is incorporated in such a part, the free length under no load and the lifting seat plate 4 will be reduced.
When the coil spring 9 is lowered, the elongation of the coil spring 9 becomes extremely large, making it difficult to select the spring constant. Also,
There is also a structure in which a coil spring is incorporated between the lower end of one of the links and the supporting portion at one end of the base, but even with this arrangement, the result is not much different from the structure shown in FIG. 6.

<Means for Solving the Problems> The present invention was made to solve the above problems, and uses an X-shaped link driven by electric or hydraulic power, and a spring element between the links. This is an improved lifting device that incorporates a spring element so that the spring element always acts in the direction of pushing up the load, and one end of the spring element is rotatably attached to one fixed point on the base side. The other end of the spring element is rotatably jointed from the midpoint of the link on this side to a point on the load pedestal side, and one end of the spring element is connected to the center of rotation of the link end fixed to the base. The spring element is rotatably fixed to the shaft, and the other end of the spring element is rotatably jointed from the midpoint of the link on this side to a point on the load holder side, or one end of the spring element is fixed to the base on the base. It is rotatably mounted coaxially with the roller at the end of the link that moves along the guide rail.
The other end of the spring element is rotatably jointed from the midpoint of the link on this side to a point on the load pedestal side, and one end of the spring element is rotatably connected to a fixed point on one of the load pedestals. The other end of the spring element is rotatably joined to a point on the base side from the midpoint of the link on this side.

<Function> Since the present invention has the above-described configuration, when any load is applied to the load receivers at the upper ends of the pair of X-shaped links, the spring elements between each link act to reduce the load.

Then, when the movable sides of the pair of X-shaped links are horizontally moved by some driving means, the load pedestal is raised and lowered by the action of the X-shaped links, thereby raising and lowering the load.

<Embodiment> FIG. 1 shows an embodiment of the present invention, in which the center points of links 11 and 12 of equal length are rotatably connected by a pin 13.
An X-shaped link is constructed, and this X-shaped link is a pair of left and right. The lower end of the link 11 is rotatably attached to a bearing 15 on the base 14 with a pin 16.
The roller 17 at the lower end of the other link 12 is connected to the base 1
It is placed on a guide rail 18 on the top 4 so that it can move smoothly.

The upper end of the link 12 is rotatably attached to a bearing 22 at the lower end of the load holder 20 by a pin 23, and the roller 24 at the upper end of the link 11 supports the lower part of the load holder 20 so that it can move smoothly. .

Bearings 26 and 27 are provided at both ends of the guide rail 18, and these bearings rotatably support a horizontal ball screw shaft 28. A ball nut 29 is screwed onto the screw shaft 28, and the ball nut 29 The side portion of the roller 17 is rotatably supported by the shaft 30 of the roller 17.

A worm foil 3 is attached to the end of the ball screw shaft 28.
2 is fixed, a worm 33 is engaged with this worm wheel 32, and this worm 33 is rotated forward and backward by an actuator 34 such as an electric motor or a hydraulic motor.
Rotate the link 12 together with the ball nut 29.
Move the bottom edge of the horizontally.

36 is a spring element; in the case of FIG.
the lower end of which is rotatably supported by the pin 16;
The upper end of the spring element 36 is connected to the link 1 by a pin 37.
It is rotatably connected to a convex portion 38 provided slightly above the center of 2.

The spring element 36 is, for example, a gas spring in which cylinders of different diameters are slidably fitted and compressed gas is sealed inside.

In addition to the method of supporting the slide-side lower and upper ends of the links 11 and 12 with the rollers 17 and 24 as described above, there is also a method of supporting them with slide bearings.

In the above first implementation row, when a target load is placed on the load pedestal 20, the load pedestal 20
When 0 falls, spring element 36 is compressed to counteract the load.

In this state, when the actuator 34 is operated to rotate the ball screw shaft 28 in the forward or reverse direction via the worm 33 and the worm wheel 32, the ball nut 2
9 moves back and forth to change the angle of inclination of the links 11 and 12 to raise or lower the load holder 20.

In the above operation, the spring element 36 always opposes the downward load on the load pedestal 20.

Therefore, by appropriately selecting the elasticity of the spring element 36, all or part of the load can be borne.

In the embodiment shown in FIG. 2, the lower end of the spring element 36 is rotatably attached to the mounting shaft 30 of the roller 17 at the lower end of the link 12, and the upper end of the spring element 36 is rotatably attached to the protrusion 38 in the middle of the link 11 using a pin 37. It can be installed freely.

In the embodiment shown in FIG. 3, the lower end of the spring element 36 is rotatably attached to a bearing 42 on the base 14 by a pin 43, and the upper end of the spring element 36 is rotatably attached to the middle of the link 12 by a pin 37. In the embodiment shown in FIG. 4, the lower end of the spring element 36 is rotatably attached to the middle of the link 11 by a pin 45, and the upper end of the spring element 36 is rotatably attached to a bearing 47 at the lower part of the load receiver 20 by a pin 48. It is installed.

In any of the embodiments shown in FIGS. 2 to 4 above, the structure other than the mounting portion of the spring element 36 is
Since it is exactly the same as the embodiment shown in the figure and its operation is also the same, detailed explanation will be omitted.

<Effects> As described above, this invention has an extremely simple structure in which a gas-type spring element is incorporated into an X-shaped link (Jissors-type link), and all or part of the load applied to the load holder is transferred to the spring element. This reduces the amount of work that must be done by the motor and other actuators that drive the load pedestal, making it possible to downsize the actuator and reduce the weight of the device. However, in particular, in this invention, one end of the spring element is rotatably attached to one fixed point on the base side, the rotation center shaft or roller shaft on the base side of the link, and the other end of the spring element is attached to the other end of the spring element. The spring element can be rotatably jointed from the midpoint of the link on this side to a point on the load cradle side, or one end of the spring element can be rotatably attached to one fixed point on the load cradle and the other end can be rotatably joined to a point on the load cradle side from the midpoint of the link on this side. By rotatably joining the middle point of the link to a point on the base side, the spring element is always act in the direction of pushing up the load pedestal. Since the amount of expansion and contraction is significantly smaller than that of the conventional example shown in FIG. 6, the spring constant can be easily selected, and even in the case of a gas type, the compression ratio can be lowered, so there are advantages such as safety.

Therefore, the present invention is effective when used in lifting devices such as luggage lifting devices, operating tables, barber chairs, and three-dimensional wheelchairs.

[Brief explanation of the drawing]

Fig. 1 is a side view showing an embodiment of the invention, Fig. 2 is a side view showing an embodiment of the present invention;
Figures 4 to 4 are side views showing other embodiments, and Figure 5 is a side view showing another embodiment.
The figure is a side view showing one example of a conventional lifting device, and FIG. 6 is a side view showing another example of the conventional lifting device. 11, 12...link, 13, 16, 23, 37
...Pin, 14...Base, 17, 24...Roller, 20
...Load receiver, 28...Ball screw shaft, 29...Ball nut, 34...Actuator, 36...Spring element.

Claims (1)

[Scope of Claims] 1. A lifting device that uses X-shaped links driven by electric or hydraulic power and incorporates spring elements between the links so that the spring elements always act in the direction of pushing up the load, One end of the spring element is rotatably attached to one fixed point on the base side, and the other end of the spring element is rotatably joined from the midpoint of the link on this side to a point on the load receiver side. A spring-type balancer device for a lifting device, which is characterized by: 2 One end of the spring element is rotatably fixed to the rotation center axis of the link end fixed to the base, and the other end of the spring element is fixed at a point closer to the load receiver than the midpoint of the link on this side. A spring-type balancer device for a lifting device according to claim 1, characterized in that the spring-type balancer device is rotatably jointed to the bottom. 3 One end of the above spring element is rotatably attached coaxially with the roller at the end of the link that moves along the guide rail on the base, and the other end of the spring element is attached to receive a load from the midpoint of the link on this side. A spring type balancer device for a lifting device according to claim 1, characterized in that the spring type balancer device is rotatably jointed at a point on the base side. 4 One end of the spring element is rotatably attached to one fixed point of the load holder, and the other end of the spring element is rotatably jointed from the midpoint of the link on this side to a point on the base side. A spring-type balancer device for a lifting device according to claim 1, characterized in that: