JPH0750176B2 - Parallel link type support mechanism - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a weight balance device of a parallel link support mechanism that supports a supported object so that the supported object can move up and down in a vertical plane.

(Prior Art) A parallel link mechanism is used as a mechanism for supporting a relatively lightweight supported object, for example, a microscope main body of a surgical microscope so as to be vertically movable within a vertical plane.

Further, in order to support the supported object stationary at a predetermined spatial position, a weight balance device is known in which a tension or compression coil spring is installed on the diagonal of the parallel link mechanism so as to achieve weight balance with the supported object. Is.

(Problems to be Solved by the Invention) However, the conventional parallel link type supporting device has a drawback that the weight balance due to the coil spring cannot be achieved when the weight change due to the replacement or addition of the supported object is large.

The present invention has been made by paying attention to such conventional drawbacks,
It is an object of the present invention to provide a parallel link type support mechanism capable of achieving weight balance even if the weight of a supported object changes.

(Means for Solving the Problems) In order to achieve this object, the present invention provides a fixed link, and a main link whose one end is pivotally attached to an upper portion of the fixed link by a first pivot. A sub-link which is disposed below the main link in parallel with the main link, and one end of which is pivotally attached to the lower part of the fixed link by a second pivot so as to be vertically movable; At the end and the other end of the secondary link,
A parallel link mechanism including a support link for mounting a supported object pivotally mounted on a fourth pivot and a parallel link having a compression elastic member interposed between the fixed link side and the third pivot A mold supporting mechanism, wherein a movable fulcrum movable on an inclined axis that intersects with a vertical axis connecting the first and second pivots on the fixed link at a side opposite to the supported object side is provided. A parallel link type supporting device is provided on the fixed link side, and the compression elastic member is interposed between the third pivot and the movable fulcrum.

(Operation) With the above configuration, when the movable fulcrum moves on the tilt axis,
The crossing angle between the link and the compression elastic member and the length of the compression elastic member change, and the upward reaction force according to the weight change of the supported object acts on the support link of the parallel link mechanism, and the weight balance is always maintained. Can be kept.

(Embodiment) FIG. 1 shows a structure of a parallel link type support mechanism (hereinafter simply referred to as a parallel link arm) according to the present invention. The parallel link arm 10 includes a fixed link 11, a main link 12, and a support link.
The sub-link 14, the sub-link 14, the gas spring 30, and the balance adjusting mechanism 40 are included.

The fixed link 11 has an arm 111, and a shaft 112 oriented in the vertical direction is fixed to the lower surface of the arm 111. Further, 100 is an arm attached to a mount (not shown), and a bearing 101 is formed at the tip of this arm 100. Moreover, the shaft 112 is rotatably held by the bearing 101, so that the fixed link 111 can be swung in the horizontal plane.

First and second pivots 21 and 22 are planted horizontally in the upper and lower portions of the fixed link 11, and the pivots 21 and 22 respectively have a main link 12 and a sub-link 14 having a U-shaped cross section. Are connected so as to be vertically rotatable in a vertical plane. The other ends of the main link 12 and the sub link 13 are pivotally connected to third and fourth pivots 23 and 24, respectively, which are planted in the support link 13 in the horizontal direction. The fixed link 11, the main link 12, the sub link 14, and the support link 13 constitute a parallel link mechanism having the pivots 21 to 24 as intersections.

A vertical bearing 130 is formed on the support link 13, and an object to be supported, for example, a surgical microscope main body M is attached to the bearing link 130, and the rotation of the shaft is usually regulated by a tightening screw 131. Has been done.

One end of a gas spring 30, which is a compression elastic member, is pivotally connected to the pivot 23. The movable piece 41 is a handle 42
By a feed screw 43 which is rotated by, it is moved up and down along its axis 0 _3.

The axis 0 ₃ of the feed screw 43 is the tilt axis of the shaft 31 as a movable fulcrum.
It is arranged in parallel with 0 ₂ . Here, the inclination angle θ ₂ with respect to the inclination axis 0 _2, that is, the vertical axis 0 ₁ of the inclination axis, is the weight of the parallel link arm, the gas pressure of the gas spring 30 and its spring constant, and the intersection angle α between the main link 12 and the gas spring 30. Further, it can be determined mechanically or experimentally by the weight of the supported object.

The present invention shows that the weight of the supported object is 5.5 k from the mechanical analysis and the experiment.
It was found that when the inclination angle θ is in the range of 7 ° 20 ″ to 16 ° when g is 17.5 kg, it is practically acceptable.
In the illustrated embodiment, the inclination angle θ is set to θ = 12 °.

An index 44 is attached to the movable piece 41 as shown in FIG.
The formed with tilting axis 0 ₂ can be moved parallel to slot 113, the rotation of the handle 42, according to the weight W of the supported object M, to adjust the index to its corresponding weight scale weight scale 114 Thus, the movable piece 41 and the shaft 31 are moved to balance the weight.

In the present invention, the tilt axis 0 ₂ is tilted leftward with respect to the vertical axis 0 ₁ by θ instead of being tilted rightward in the figure. As a result, the one according to the present invention is very excellent in the supporting force as compared with the case where the tilt axis 0 ₂ is tilted rightward in the figure by θ with respect to the vertical axis 0 ₁ . This point will be described based on the following table. In the following table, the gas spring 30 when the tilt angle of the tilt axis 0 _{2 with} respect to the vertical axis 0 ₁ is the same and the links 12 and 14 are horizontal and the shaft 31 is moved up and down.
Represents the length, angle, component force, spring force, etc.

As can be seen from this table, when the tilt axis 0 ₂ is tilted to the right, the gas spring 30 moves up and down with the shaft 31.
When the spring force of the gas spring 30 increases or decreases, the upward component of the spring force of the gas spring 30 decreases or increases as the spring force increases or decreases. Become. On the other hand, in the present invention, even if the spring force of the gas spring 30 increases or decreases as the shaft 31 descends or rises, the upward component force of the gas spring 30 also increases or decreases. Therefore, the increase / decrease of the gas spring 30 can be effectively used.

Therefore, if the vertical movement amount of the shaft 31 is the same, the amount of change in the upward component force of the spring force is larger in the present invention than in the case where the tilt axis 0 ₂ is tilted to the right. it becomes possible to take larger than those by tilting the range of weight that can be supported on the support link 13 to the right tilting axis 0 ₂ ones. In other words, when the same range of weight that can be supported on the support link 13, it is possible to reduce the amount of movement of the shaft 31 as compared to that inclined tilting axis 0 ₂ to the right in the present invention.

(Effect) As described above, according to the present invention, the first and second
A movable fulcrum movable on an inclined axis that intersects the vertical axis connecting the second pivot with the side opposite to the supported object is provided on the fixed link side, and the compression elastic member is provided on the movable fulcrum. Since it is arranged between the third pivot and the movable fulcrum, even if there is a change in the weight of the object to be supported, the operation of the balance adjusting mechanism causes the main link with the gas spring or the like, which is a compression elastic member. By changing the angle of intersection with and the length of the compression elastic member, weight balance can be always maintained.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a support mechanism according to the present invention, and FIG. 2 is a view showing the structure of its index portion. 10 …… Parallel link arm, 11 …… Fixed link, 12 …… Main link, 13 …… Sub link, 14 …… Support link, 21 …… First pivot, 22 …… Second pivot, 23 …… Third axis, 24 ...
… 4th axis, 30 …… Gas spring (compression elastic member), 31 …… Axis (movable fulcrum), 40 …… Balance adjusting mechanism, 0 ₁ …… Vertical axis, 0 ₂ …… Inclined axis.

Claims (4)

[Claims] 1. A fixed link, a main link whose one end is pivotally attached to an upper part of the fixed link by a first pivot so as to be movable up and down, and is arranged below the main link in parallel with the main link. A sub link whose one end is pivotally attached to the lower part of the fixed link by a second pivot so as to be vertically movable, and upper and lower parts are the third and fourth ends of the main link and the other end of the sub link. A parallel link mechanism comprising a support link for mounting a supported object pivotally mounted on the pivot axis of the parallel link type support in which a compression elastic member is interposed between the fixed link side and the third pivot axis. The mechanism, wherein the movable fulcrum movable on an inclined axis intersecting the vertical axis connecting the first and second pivots on the fixed link to the side opposite to the supported object is fixed. Provided on the link side, the compression elastic member is provided between the third pivot and the movable fulcrum. Parallel link type supporting mechanism, characterized in that interposed. 2. The parallel link type supporting mechanism according to claim 1, wherein the movable fulcrum is moved by a feed screw having an axis parallel to the tilt axis as a rotation axis. 3. The parallel link type support mechanism according to claim 2, wherein the compression elastic member is a gas spring. 4. The parallel link type according to any one of claims 1 to 4, wherein an intersecting angle of the tilt axis with the vertical axis is in the range of 7 ° to 16 °. Support mechanism.