JPH0310565Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] This invention relates to a link structure of a parallel link type arm stand.

[Background technology]

For example, the parallel link type (parallel crank mechanism type) shown in FIG. 9 is often used in bed lights for hospitals and power stands for study desks.

This arm stand includes a lower hinge 2 with an arm insertion pipe 1, an intermediate hinge 3, and an upper hinge 4. These three hinges 2,
Between 3 and 4, a lower arm 5 and an upper arm 6 are provided as parallel link (parallel crank mechanism) types. The arm stand is
It is designed to be installed by inserting the arm insertion pipe 1 into a stand support base fixed to a hospital bed or the like. The lamp 7 is attached to a lamp mounting pipe 8 that protrudes from the lower hinge 4, and the lamp 7 can be installed by loosening the angle adjustment knobs 9 provided on each of the hinges 2, 3, and 4.
By moving 6 or one of the arms in parallel, it can be freely brought to the desired position. A tension spring mechanism 10 is provided to balance the movement. The lamp 7 is fixed by turning the angle adjustment knob 9 to lock it.

Both arms 5 and 6 are the first and second links 1, respectively.
1 and 12, but on the other hand, for example, taking the second link 12, the 10th link
As shown in the figure, the link 12 is composed of a pair of left and right separate plate pieces 70, 70. Both plate pieces 70, 70 are provided with a shaft insertion portion 71 at each end thereof, and are provided with a shaft insertion hole 72 in the center of the shaft insertion portion 71. A spacer pipe 73 is separately provided between both shaft insertion portions 71, and a fulcrum shaft 76 passed through one lower hinge plate 74 and an intermediate hinge plate 75 is connected to the shaft insertion hole 72 of one plate piece 70 and the spacer pipe 73. It passes through the shaft insertion hole 72 of the other plate piece 70 through the pipe 73 and into the other lower and intermediate hinge plates 74, 75.

In this way, the link consisting of the pair of plate pieces 70, 70 is constructed with a gap between them because it is necessary to pass the tension spring mechanism 10 between them, but as described above, the link member (plate piece ) are configured as separate left and right parts, the assembly becomes very troublesome because the spacer pipe 73 also needs to be assembled at the same time and the parts are small. Moreover, the distance L between the two shaft insertion holes 72, 72 in one link member,
The distance L' between the shaft insertion holes 72, 72 in other link members often differs due to processing considerations. If the distances L and L' are different in this way, both shaft through holes 7 are formed on the fulcrum shaft 76.
2 becomes difficult to match, making it difficult to assemble.Moreover, if you forcibly assemble things that are difficult to match, there will be resistance to the movement of the parallel link mechanism later, making it impossible to move the lamp 7 smoothly. Further, there is a problem in that stress is concentrated on the shaft insertion portion 71 where force is applied to the shaft insertion hole 72 on the side that is forcibly aligned. In order to deal with this stress concentration by increasing the strength, the width around the shaft insertion hole 72 of the shaft insertion portion 71 is increased, and the shaft insertion portion 71 is
Although it is possible to increase the dimension R related to the strength up to the edge of the arm, if it is made too large, the width of the entire arm consisting of the first and second links 11 and 12 also increases, which impairs the appearance. There is.

[Purpose of invention]

In view of the above circumstances, this invention allows for easy and accurate assembly, prevents hindrance to the movement of the link after assembly, and increases the strength of the shaft insertion portion without increasing the size of the entire link. It is an object of the present invention to provide a link structure for a parallel link type arm stand.

[Disclosure of invention]

In order to achieve the above object, the link structure of the parallel link type arm stand according to the present invention includes a link member having a pair of left and right strip-shaped plate pieces with their plate surfaces facing each other, which is attached to one of the parallel link type arms. In the link structure of a parallel link type arm stand provided as a link, both the plate pieces are integrally formed by bending one plate, and
A shaft insertion portion is integrally formed at both ends thereof.

This invention will be explained in detail below with reference to drawings showing embodiments thereof.

Figures 1 and 2 show an example of the link structure of the parallel link type arm stand according to this invention in cross section, Figure 3 shows its schematic diagram, and Figure 4 shows its exploded view. . As shown in these figures, the arm stand has a lower arm 15.
and an upper arm 16, and a lower hinge 1 at the lower end of the lower arm 15.
7, the upper end of the upper arm 16 has an upper hinge 18
is provided. The upper and lower arms 15 and 16 are bendably connected by an intermediate hinge 19.

The lower arm 15 consists of a lower first link 20 formed of a square pipe and a lower second link (tension metal plate) 21. The lower second link 21 is passed through the lower first link 20. The lower hinge 17 includes a pair of lower hinge plates (hinge mounting plates) 22 , 22 and a lower hinge cover 23 . Both lower hinge plates 2
A connecting block 25 having an arm insertion pipe (arm insertion port) 24 is sandwiched between 2 and 22 and tightened with a mounting screw 26.
A first fulcrum shaft 27 is passed between the fixed lower hinge plates 22, 22, and this first fulcrum shaft 2
7 allows the lower first link 20 to rotate freely. A lower hinge cover 23 is provided on the outside of both lower hinge plates 22, and this cover 23 can be moved through the lower hinge plate 22 by turning an angle adjustment knob 28.
Rotation of the link 20 can be allowed or locked. A second fulcrum shaft 29 is passed between the lower hinge plates 22, 22 as a fulcrum. This second fulcrum shaft 29 is designed to rotatably support the lower ends of both the lower second links 21, and here, the lower first link 21 is rotatably supported.
The second fulcrum shaft 29 is inserted into the end notch 30 provided at
By passing through, even if the first lower link 20 rotates and stands up, the fixed second fulcrum shaft 29 and the rotating lower first link 20 do not interfere with each other.

The upper end of the lower first link 20 has a central end through hole 31' and a second fulcrum shaft guide groove 32 on its outer periphery.
is provided. Intermediate hinge plate 33,3
The first fulcrum shaft 27 passed through the end through hole 3
1' and the other first fulcrum shaft 27, which is passed between the intermediate hinge plates 33, 33, is passed through the end through hole 31 of the upper first link 20. One of the second fulcrum shafts 29, which is passed between the intermediate hinge plates 33, 33, is inserted into the second fulcrum shaft guide groove 32 and can slide within the groove. intermediate hinge plate 33,
33, the other second fulcrum shaft 29 passes through the end notch 30 of the upper first link 20
It is connected to one end of the link 21. The intermediate hinge cover 23 provided on the outside of the intermediate hinge plates 33, 33 also has the same function as the lower hinge cover 23 at the lower end of the lower arm 15. Furthermore, regarding the upper hinge 18, the intermediate hinge 19
The lamp 36 is attached to the lamp mounting pipe 35 that protrudes from the upper hinge plate 34.
is now ready to be installed. The lower arm 15 and the upper arm 16 each constitute a parallel link mechanism.

Upper and lower arms 1 made up of these parallel link mechanisms
5 and 16, a tension spring mechanism 40 for obtaining the balance mechanism is provided so as to intersect with each link 20 and 21.

In the arm stand configured as described above, the second link 21 is configured as follows. In other words, as shown in FIG. 6, the second link 21 includes a pair of left and right strip-shaped link plate pieces 41,
, connecting portions 42, 42 integrally provided between both ends of both link plate pieces 41, 41, and each connecting portion 42.
It is formed as an integral link with a shaft insertion part 43 that is formed in a rolled-up shape so as to be integrated with the tip of the link. Both link plate pieces 41, 41 have a distance W
Each of the shaft insertion portions 43 is formed into a cylindrical shape, and a shaft insertion hole 44 is provided on the inner circumference thereof. As shown in FIG. 1, the second link 21 has a shaft insertion portion 43 at one end connected to a second fulcrum shaft 29 passed through the lower hinge plate 22, and a shaft insertion portion 43 at the other end. is connected to another second fulcrum shaft 29 passed through the intermediate hinge plate 33. The second fulcrum shaft 29 at the upper end can move along an arc-shaped second fulcrum shaft guide groove 32 formed in the first link 20, and the second fulcrum shaft 29 at the lower end can move along a second fulcrum shaft guide groove 32 formed in the first link 20. It passes through an end notch 30 formed at the lower end of the first link 20. The distance W is provided to allow a tension spring mechanism 40 consisting of a coil spring 45 and a spring end pipe 46 to pass through, as shown in FIGS. 6 and 7. Further, a cord (lead wire) 48 connected to the lamp 36 is passed through the tension spring mechanism 40 . As shown in FIG. 1, this tension spring mechanism 40 has a
In this example, as shown in the schematic diagram of FIG. 3, the tension spring mechanism 40 crosses both links 20 and 21. It is said that a large spring elongation rate can be obtained because the spring is curved.

The link has two plate pieces 41, 41 which are integrally formed by bending one plate, and shaft insertion portions 43 are integrally formed at both ends thereof. The spacer pipe and the spacer pipe can be assembled together easily and reliably, improving the ease of assembly. In addition, since the shaft insertion portion 43 can be integrally molded as described above, there is no variation in the pitch of the mounting holes of both plate pieces, unlike in the past, and the center distance between the shaft insertion holes 44 is eliminated. Since the dimension L of is always constant, it is easy to assemble, and the dimensional accuracy of the entire link structure is improved.Furthermore, it is not only possible to provide a link with low resistance as a parallel link mechanism, but also , stress will not be concentrated on one plate piece. Furthermore, as shown in the above embodiment, if the shaft insertion part 43 is made into a cylindrical shape, the strength is increased and there is no concentration of stress, and the link plate piece 41
The width of the plate itself can also be made sufficiently small. When the width of the link plate piece 41 becomes smaller, the cross-sectional size of the first link 20 that accommodates it also becomes smaller, and as a result, as shown in FIG. 5, it is possible to provide an arm that is slim and has an excellent appearance. It is something.

In the above embodiment, the arm is bent at two points, but it may be bent at one point or at three or more points.
Further, in the above embodiment, the first link is a pipe and the second link is housed inside the pipe, but it may be of a type in which both links are exposed. In the embodiment, the shaft insertion portion 43
was formed by simultaneous integral molding, but the 8th
As shown in the figure, the shaft insertion portion 43 may be formed separately from a cylindrical body and may be attached to the connecting portion 42 later by welding or the like.

[Effect of idea]

As seen above, the link structure of the parallel link type arm stand according to this invention is such that a link member having a pair of left and right strip-like plate pieces with their plate surfaces facing each other is used as one link of the parallel link type arm. In the link structure of the parallel link type arm stand, the plate pieces are integrally formed by bending a single plate, and shaft insertion portions are integrally formed at both ends thereof. This feature allows for easy and accurate assembly, prevents any hindrance to the movement of the link after assembly, and increases the strength of the shaft insertion part without increasing the size of the entire link. It is something.

[Brief explanation of drawings]

Figure 1 is a longitudinal side view of the entire stand showing an example of the link structure of the parallel link type arm stand according to this invention, Figure 2 is a half sectional view of the lower part seen from one side, and Figure 3 is the parallel link type arm stand. A schematic diagram of the link mechanism, FIG. 4 is an exploded perspective view of the arm stand in FIG. 1, FIG. 5 is a perspective view showing the external appearance of the arm stand, and FIG.
A perspective view showing the structure of the link, Figure 7 is the second
FIG. 8 is a perspective view showing a cross section of a state where the link and the tension spring mechanism are housed in the first link; FIG. 8 is a perspective view showing another example of the second link; FIG. 9 is a perspective view showing another example of the second link;
The figure is a side view of a conventional arm stand, and FIG. 10 is an exploded perspective view showing the mounting structure of the second link. 15, 16... Arm, 20, 21... Link, 41... Link plate piece, 43... Shaft insertion portion.

Claims (1)

[Claims for Utility Model Registration] (1) A parallel link type arm stand comprising, as one link of a parallel link type arm, a link member having a pair of left and right strip-shaped plate pieces with their plate surfaces facing each other. In the link structure, both plate pieces are integrally formed by bending one plate, and shaft insertion portions are integrally formed at both ends of the parallel link type arm stand. link structure. (2) The link structure of the parallel link type arm stand according to claim 1 of the utility model registration claim, in which the shaft insertion portion is formed in a cylindrical shape. (3) The link of the parallel link type arm stand according to claim 1 or 2 of the utility model registration claim, in which the shaft insertion portion is integrally formed by being fixed by welding to both plate pieces that are integrally formed. structure. (4) From claim 1 of the utility model registration claim, in which the link member is inserted through another cylindrical link member, and a tension spring mechanism for balance is disposed between both plate pieces of the link member. The link structure of the parallel link type arm stand according to any one of items up to 3.