JPH0351420B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to footrest mechanisms for dental chairs, barber and beauty salon chairs, operating tables, wheelchairs with a reclining function, and the like.

<Prior art> As a first conventional example, the rotational movement accompanying the reclining of the footrest of various conventional chairs with a reclining function uses a mechanism that simply rotates the footrest around a single axis, as shown in Fig. 4. There is.

That is, in FIG. 4, 1 is a seat plate, 2 is a backrest connected to the rear end so as to be rotatable about an axis 3, and 5 is a footrest, which is attached to the front end of the seat plate 1 and is connected to the backrest about an axis 4. It is connected so that it can rotate freely.

When the back support 2 is raised as shown by the chain line, the footrest 5 is rotated downward as shown by the chain line.

<Problems to be Solved by the Invention> In the above-described device, the footrest 5 rotates around one axis 4, so as the footrest 5 rotates around one axis 4, the distance between the footrest 5 and the heel 6 of the foot changes as shown by the solid line to the chain line. A gap 7 occurs between them. Because of this deviation 7, for example, if the footrest 5 is set to a length that can hold the heel of the human body 8 in the supine position, the tip of the footrest 5 may interfere with the floor surface when transformed into a chair position. A problem arose.

As a countermeasure, it is possible to set the footrest short to prevent interference with the floor surface.
In this case, the feet of the seated person protrude from the footrest to the extent that the footrest is shortened, making it impossible to achieve the footrest function. On the other hand, if you set the footrest to a long dimension and leave it to interfere with the floor, the footrest will not be able to fit under the chair, and your feet will touch the footrest when you sit down, making it difficult to use. There are some disadvantages.

Therefore, as a second conventional example,
A foldable frame structure described in Japanese Patent No. 49138 is known. This invention, as shown in FIG. 15 of the publication, consists of arms A'1,
Footrests F1 and F2 are rotatably attached to A'2, and the footrests F1 and F2 are
is kept in a horizontal position.

However, in this conventional example, the footholds F1 and F2
Since the wheelchair is configured to rotate in the width direction of the wheelchair around the arms A'1 and A'2, the footrests F1 and F2 protrude to the outside of the chair when the user is not seated. Therefore, similar to the first conventional example, when the user sits down, his or her feet may come into contact with the footrests F1 and F2, causing a practical inconvenience.

This invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a footrest mechanism that can prevent interference between the footrest and the floor surface of a chair with a reclining function without shortening the size of the footrest. .

<Means for Solving the Problems> The present invention has been made to solve the problems described above, and includes connecting an upper link and a lower link to a fixed column so as to be able to rotate vertically. The rear end of the third link is rotatably connected to the free end of the
A point near the center of the third link and a point near the center of the upper link are rotatably connected to each other, a fourth link is rotatably connected to the free end of the upper link, and the third link is rotatably connected to a free end of the upper link. The free end of the upper link and the free end of the fourth link are rotatably connected to the front and rear of the fifth link, a footrest is fixed to the fifth link, and the upper link is centered around the connection point to the fixed column. When rotating downward, the fifth link is rotated in a non-parallel state with respect to the fixed column, so that each link is folded.

<Function> Since the present invention has the above structure, the footrest is fixed to the fifth link so that the footrest becomes horizontal when raised.

When the footrest is rotated downward from the above state, the upper link and lower link rotate downward around the connecting shaft to the fixed column, and at the same time the third and fourth links rotate downward.
The link also rotates, but when the lower link rotates downward, the third link connected to it rises upward around the connecting axis with the lower link and descends.
and retreat.

When the lower link descends and rises upward in this way, the fourth link also rises upward and descends around the connection axis with the upper link, and then retreats.

Therefore, the fifth link, which is rotatably connected to the tips of the third link and the fourth link, is in a non-parallel state with respect to the fixed column, that is, rises upward, descends, and retreats. The footrest fixed to the 5 link moves backward while rotating downward.

For this reason, even if the footrest fixed to the fifth link is made to extend sufficiently long when it is horizontal, the amount of descent when descending is relatively small.
Even when the footrest is lowered, it does not interfere with the floor.

<Example> Next, an example of the present invention will be described based on FIGS. 1 to 5 of the accompanying drawings.

In the figure, 11 is a fixed column, and 12 and 13 are upper and lower links rotatably connected to the upper and lower portions of the fixed column 11 by shafts 14 and 15.

The rear end of the third link 16 is rotatably connected to the tip of the lower link 13 by a shaft 17, and the rear end of the third link 16 is slightly rearward from the middle part of the third link 16 and slightly forward from the center of the upper link 12. The points are rotatably connected by a shaft 18. The tip portion of the upper link 12 protrudes outside the third link 16.

The rear end of the fourth link 19 is rotatably connected to the tip of the upper link 12 by a shaft 20, and the rear end of the fifth link 21 is connected to the tip of the third link 16 and the fourth link 19. The intermediate portion is rotatably connected to the intermediate portion by shafts 22 and 23. Then, the footrest 24 is fixed onto the fifth link 21.

In FIG. 1, the footrest 24 is placed horizontally so that it is in the same horizontal plane as the seat plate 25 fixed to the fixed column 11. When the footrest 24 is rotated downward from this state, the upper and lower links 12 are aligned as shown in FIG. ，
13 and 3rd, 4th link 16, 19 and 5th link
The link 21 is folded to make the headrest 24 face down.

Figure 3 shows an example of the dimensions of each part, where a between the shafts 15 and 17 is 157 mm, and b between the shafts 14 and 18 is 195 mm.
mm, c between axes 18 and 20 is 80 mm, between axes 17 and 18e is 77 mm, d between axes 18 and 22 is 172 mm, axes 20 and 2
f between 3 is 167mm, g between shafts 22 and 23 is 81mm, shaft 1
The h between 4 and 15 is 120 mm. And the shaft 14,
The angle between the line segment connecting 18 and the line segment connecting axes 18 and 20 is 4 degrees, and the angle between the line segment connecting axes 17 and 18 and axes 18 and 2
The angle formed by the line segment connecting 2 is 7°.

FIG. 5 shows the positional state when the footrest 24 is rotated in comparison with a conventional example.

First, when the footrest 24 rotates downward from the horizontal state, the upper link 12 and lower link 13 rotate downward around the connecting shafts 14 and 15 to the fixed column 11, and at the same time, the third link 16 and the fourth link 19 also rotates, but when the lower link 13 rotates downward,
The third link 16 connected to this is the lower link 13
It rises upwards and descends around the connecting shaft 17, and then retreats.

When the lower link 13 descends and rises upward in this way, the fourth link 19 also rises upward and descends around the connection axis with the upper link 12, and then retreats.

Therefore, the fifth link 21 is rotatably connected to the tips of the third link 16 and the fourth link 19.
The footrest 24 fixed to the fifth link 21 moves in a non-parallel state with respect to the fixed column 11, that is, rises upward, descends, and retreats.
moves backward while rotating downward. That is, the amount of descent of the footrest 24 is reduced by the length L shown in the figure.

For this reason, even if the footrest 24 fixed to the fifth link 21 is made to extend sufficiently long when it is horizontal, the amount of descent is relatively small as described above, so even if the footrest is lowered, it will not interfere with the floor surface. There is no such thing.

As a result, it is not necessary to design the footrest 24 to be short or to take measures to prevent a person's feet from getting caught on the footrest 24, and the practical value is significantly improved.

<Effects of the Invention> The present invention has the following effects due to the above structure.

That is, the fifth link to which the footrest is attached is supported by two links, the third and fourth, and these two links are connected to the two links, the upper link and the lower link, which are supported by the fixed column. When the footrest is rotated downward from the horizontally extending position above the fixed column, each link is folded while the fifth link rotates non-parallel to the fixed column. Compared to a model that rotates around a fixed fulcrum, the ground clearance at the lowest end is higher.

Therefore, even if the footrest is sufficiently long when extended horizontally, it will not interfere with the floor when rotated downward to the sitting position, making it suitable for use in dental chairs, barber shops, beauty salon chairs, and operating tables. It is effective when used as a footrest for a wheelchair with a reclining function.

[Brief explanation of drawings]

Fig. 1 is a side view showing an embodiment of the footrest function of the present invention, Fig. 2 is a side view of the same in the folded state, Fig. 3 is a side view showing an example of the dimensions of each part of the above, and Fig. 4 is FIG. 5 is a side view showing an example of a conventional footrest mechanism, and is an explanatory diagram of an operating state for comparing the present invention and a conventional example. 11...Fixed pillar, 12...Top link, 13...
Lower link, 14, 15, 17, 18, 20, 2
2, 23... Axis, 16... Third link, 19...
4th link, 21...5th link, 24...footrest, 25...seat plate.

Claims (1)

[Claims] 1. In a footrest mechanism in which a footrest is attached to a chair with a reclining function and the footrest is rotated in conjunction with the reclining movement of the chair, the upper link and the lower link can be rotated vertically with respect to a fixed column fixed to the chair. a rear end of the third link is rotatably connected to the free end of the lower link, and a point near the center of the third link and a point near the center of the upper link are rotatably connected to each other. death,
A rear end of a fourth link is rotatably connected to the free end of the upper link, and a free end of the third link and a free end of the fourth link are rotatably connected to the front and rear of the fifth link. Then, when a footrest is fixed to this fifth link and the upper link is rotated downward around the connection point to the fixed column, the fifth link is rotated in a non-parallel state with respect to the fixed column. A footrest mechanism characterized by folding each link.