JPH0453709Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a seat height-adjustable chair whose seat can be raised and lowered by a lifting device equipped with an X-link mechanism.

[Prior Art] As this type of chair, a type called a so-called piano chair is known. In this type of chair, the seat is supported on the seat support part of the chair body via a lifting device, and the lifting device has a pair of left and right X link mechanisms that horizontally connect the seat to the chair body. and a lifting position adjustment mechanism for fixing the seat to the chair body in a height-adjustable manner. As is well known, the elevating position adjustment mechanism for this type of chair is achieved by fixing a locking rod to the chair body and extending downwardly a rotating arm having a plurality of engagement recesses in the seat. The seat is fixed at a specific height position by engaging one of the engaging recesses of the rotating arm with the locking rod. In this device, an operating lever is connected to the rotating arm, and by operating the operating lever to temporarily move the rotating arm away from the engagement position, the locking rod can be connected to the locking rod. The engaging recesses to be engaged can be changed as appropriate, and the vertical position of the seat can be adjusted by operating the engaging recesses.

[Problems to be solved by the invention] However, in such a conventional chair, the engagement recesses of the rotating arm provided intermittently are selectively engaged with the locking rod. , stepless adjustment of sitting height is not possible. Some devices have been able to achieve substantially stepless adjustment by increasing the number of adjustment steps by using a plurality of locking rods, but this method has the problem of complicating the structure.

Furthermore, in this case, when an external force is applied to the operating lever and the engagement recess of the rotating arm and the locking rod are disengaged, the seat falls all at once. Therefore, for example, if another person applies excessive force to the operating lever while sitting on the chair, the rotation arm and locking rod may disengage and the seat may move to the lowest position. It may fall to a certain position and cause a big shock to the person sitting on it. Furthermore, if a hand or foot is inserted between the seat and the chair body at that time, the seat under load may fall, causing irreversible damage. One possible measure to prevent such inconvenience is to provide a locking mechanism to the operating lever, etc., but adding such a locking mechanism not only increases the number of parts and complicates the structure. A problem arises in that operations become complicated.

The purpose of this invention is to provide a seat height-adjustable chair that can solve the above-mentioned problems and has a good balance of operability and stability while maintaining an affordable weight. There is.

[Means for Solving the Problems] In order to achieve the above-mentioned objects, the present invention provides a chair in which a seat is supported on a chair body so that the seat height can be adjusted via a lifting device. , the first link member and the second link member are rotatably connected to each other by a fulcrum pin at their longitudinal center portions. A pair of left and right X link mechanisms, an upper stay installed between the corresponding first link members of both the X link mechanisms, and an upper stay located below the upper stay.
A lower stay installed between the second link members of the link mechanism, and the lower stay is screwed into a vertical screw hole provided in the lower stay, and its upper end is connected to the upper stay so as to be rotatable and immovable in the axial direction. the screw shaft, and an operation handle that rotates the screw shaft to change the distance between the two stays; A connection point of the upper stay to the first link member is set in a region of 1/3 of the center part between the upper end of the link member, and a middle part between the pivot point and the lower end of the second link member. The present invention is characterized in that a connecting point of the lower stay to the second link member is set in a 1/3 area.

[Function] With this configuration, when manufacturing the X-link mechanism that forms the center of the lifting device,
The first link members on the left and right are rigidly connected, and the second link members on the left and right are rigidly connected in the same way. Then, by overlapping them and caulking the fulcrum pin, each link member can be rotated. Can be connected to. Therefore, manufacturing is simplified, and the distance between the link members to be caulked by the fulcrum pin is short and the link members can be caulked individually.
Caulking can be performed reliably, and safety at the connecting portion of link members is improved.

In addition, when in use, when the screw shaft is rotated by operating the operation handle, the screw shaft screws into the lower stay and advances and retreats, and the distance between the lower stay and the upper stay changes steplessly. do.
As a result, the intersection angle between the first link member and the second link member of the X link mechanism changes, and the height of the seat changes.

Therefore, in this chair, the sitting height can be adjusted steplessly according to the amount of rotation of the operating handle. In addition, since it is possible to provide a self-locking function to the threaded part of the screw shaft,
When the operation is stopped, the seat is automatically locked in that position, so even if an unexpected external force is applied, the seat will not fall suddenly.

By the way, when a load is applied to the seat of this chair from above, a force is applied to the first and second link members in a direction that reduces their intersection angle, and this force acts on the upper stay and the lower stay. is transmitted to the screw shaft via the Therefore, a bending moment proportional to the load placed on the seat acts on the upper stay and the lower stay. In this case, if the connection points of the upper stay and the lower stay to the link members are set near the pivot points of the link members, a very large bending moment will act on both the stays due to the lever action. Therefore, in order to ensure the rigidity (stability) of the lifting device, it is necessary to make both stays thick and strong. However, the proposed method is
Since the connecting point is set in the central ⅓ region, there is a relatively long distance between the connecting point and the pivot point. Therefore, the load acting on the seat is not excessively increased and acts on the stay, and both stays can be made relatively slender and lightened appropriately. On the other hand, if the connection points of both stays to the link member are set near the ends of the link member, the amount of change in the distance between the upper stay and the lower stay becomes close to the amount of elevation of the seat.
Therefore, not only is it necessary to make the screw shaft long, but also the amount of operation relative to the amount of elevation and descent of the seat becomes excessive, resulting in difficulties in operability. On the contrary,
In the device of the present invention, the connection point is set in the central 1/3 area as described above, so it is possible to secure a relatively large distance between the connection point and the end of each link member. can. Therefore, the approaching and separating movements of both stays are amplified by the X-link mechanism and transmitted to the seat. Therefore, it is possible to raise and lower the seat relatively quickly with an appropriate amount of operation.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

As shown in FIGS. 1 and 2, this chair includes a chair body 1, a seat 2 that can be raised and lowered relative to the chair body 1, and a seat 2 that can be raised and lowered between the seat 2 and the chair body 1. It is equipped with a device 3.

The chair body 1 is, for example, made of wood and has an integral backrest 11, and a horizontal seat support part 12 located below the seat 2 has front and rear horizontal members 14 between left and right side plates 13, 15 is constructed in the form of a frame. And, the seat support part 1 of this chair body 1
2 and the seat 2, the lifting device 3 is provided.

The elevating device 3 includes a pair of left and right X link mechanisms 4 that connect the seat 2 to the chair body 1 in order to raise and lower it in a constant posture, and an elevating position adjustment mechanism 5 that allows the elevating position of the seat 2 to be changed by manual operation. It is equipped with.

As shown in FIGS. 3 and 4, each X link mechanism 4 includes a first link member 41 in the shape of an elongated plate,
A second link member 42, which is also in the form of an elongated plate, is rotatably connected at the center by a fulcrum pin 43, and the upper end 41a of the first link member 41 and the upper end 42b of the second link member 42 are connected via the upper bracket 6. Connected to Sagittarius 2 and the 1st
The lower end 41b of the link member 41 and the lower end 42a of the second link member 42 are supported by the seat support portion 12 of the chair body 1 via the lower bracket 7. In addition, specifically, the first link member 41
The upper end 41a and the lower end 42a of the second link member 42 are pivotally connected to the vicinity of the front ends of the corresponding upper bracket 6 and lower bracket 7 via pins 41c and 42c. Further, a pin 42d and a pin 41d are horizontally protruded from the upper end 42b of the second link member 42 and the lower end 41b of the first link member 41, respectively, and the pins 42d and 41d are connected to the rear end of the upper bracket 6. It is rotatably and slidably inserted into a horizontal long hole 61 extending in the front-rear direction provided in the lower bracket 7 and a horizontal long hole 71 extending in the front-rear direction provided near the rear end of the lower bracket 7, respectively. Note that between the parts near the upper end of the first link member 41 and the parts near the upper end of the second link member 42,
Connection bars 44 and 45 are provided respectively to prevent the left and right X link mechanisms 4 from moving differently. The connecting bars 44 and 45 are pipe-shaped and are rigidly attached to the corresponding link members 41 and 42 by welding. Assembling the X link mechanism 4 is as follows:
First, connect the connecting bar 44 to the left and right first link members 41.
firmly attached by welding, and then the second left and right
A connecting bar 44 is rigidly attached to the link member 42. Next, the first link member 41 and the second link member 45, which are connected by the connecting bars 44 and 45, are stacked on each other at their center portions on the left and right sides, and the fulcrum pins 43 are individually caulked, and the first and second link members 41 , 42 are rotatably connected to complete the assembly. In this way, the first and second link members 4
By connecting the portions near the upper ends of the first and second link members 41 and 42, in other words, the portions outside the pivot points of the first and second link members 41 and 42, by connecting bars 44 and 45, twisting force applied to the X link mechanism 4 can be reduced. It is possible to increase the proof strength against. In other words, the overall rigidity of the X-link mechanism 4 is increased, and safety is improved. The link members 41 and 42 of the X link mechanism 4 constructed as described above are engaged with stays 51 and 52, which will be described later, of the elevation position adjustment mechanism 5.

As shown in FIG. 3, the elevating position adjustment mechanism 5 is
The upper stay 51 is installed between the first link members 41 of both the X link mechanisms 4, and the second link member 4 is positioned below the upper stay 51.
A lower stay 52 is installed between the lower stay 52 and the lower stay 52 is screwed into a vertical screw hole 52c provided in the lower stay 52, and its upper end 53a is connected to the lower stay 51 so as to be rotatable and immovable in the axial direction. Screw shaft 5
3, and an operating handle 5 that rotates the screw shaft 53 to change the distance between the stays 51 and 52.
4. The upper stay 51 is shaped like a rectangular pipe, and has end plates 51a covered on the left and right sides of the upper stay 51.
A connecting pin 51b is provided in a protruding manner. The connecting pin 51b is rotatably connected to the first link member 41. The connection point a of the upper stay 51 to the first link member 41 is from the pivot point n between the first link member 41 and the second link member 42 to the upper end 41a of the first link member 41.
It is set within area A in the central 1/3 of the area. The lower stay 52 is shaped like a square pipe, and connecting pins 5 are attached to end plates 52a covered on the left and right sides of the lower stay 52.
2b is provided protrudingly. And the connecting pin 52
b is rotatably connected to the second link member 42. The connection point b of the lower stay 52 with respect to the second link member 42 is located at a central portion 1 between the pivot point n of the first link member 41 and the second link member 42 and the lower end 42a of the second link member 42. It is set in area B of /3. In addition,
The screw hole 5 is located in the center of the lower stay 52.
A nut (not shown) forming 2c is embedded.

Next, the operation of this embodiment will be explained. As shown in FIG. 4, when the seat 2 is lowered, the operating handle 54 is rotated in a desired direction to thread the screw shaft 53 into the screw hole 52c and raise it.
This screw shaft 53 uses the lower stay 52 as a foothold to push the upper stay 51 upward. As a result, both link members 41, 4 of the X link mechanism 4
2 operates in the direction of increasing the crossing angle to raise the seat 2. If the rattling and deflection of various parts are ignored, the seat 2 will always rise while being kept horizontal due to the posture maintaining action of the X-link mechanism 4. When the operation handle 54 is rotated in the opposite direction, the screw shaft 53 is screwed into the screw hole 52c and lowered, and the seat 2 is screwed down by the operation opposite to that described above.
descends while maintaining a horizontal position.

The seat height can be adjusted steplessly in the above manner, but since the threaded portion of the screw shaft 53 can be provided with a self-locking function, the seat 2 can be adjusted as soon as the operation is stopped. Since it is automatically locked in that position, it is impossible for the seat 2 to suddenly fall even if an unexpected external force is applied.

Furthermore, when a load is applied to the seat 2 of this chair from above, a force is applied to the first and second link members 41 and 42 in a direction that reduces their intersecting angle, and this force is applied to the upper stay 51. and is transmitted to the screw shaft 53 via the lower stay 52. Therefore, the upper stay 51 and the lower stay 52
A bending moment corresponding to the load placed on the seat 2 acts on the seat 2. In this chair, the connecting points a and b of the stays 51 and 52 to the link members 41 and 42 are connected to the central portion 1/ 3 area A,
B, the distance between the connecting points a, b and the pivot point n is relatively larger than, for example, when the connecting point is set near the pivot point n. Therefore, an extremely large bending moment does not act on the upper stay 51 and the lower stay 52, and it is possible to obtain the necessary strength and rigidity without making both the stays 51 and 52 extremely strong. becomes. Therefore, both the stays 51 and 52 can be made into relatively thin pipe-shaped ones, thereby making it possible to appropriately reduce the weight.

In addition, the connecting points a and b are connected to the center 1/3 of the above-mentioned
If set in areas A and B, their connection points a,
b, and the end portion 41a of each link member 41, 42,
A relatively large distance can be secured between it and 42a.
Therefore, the approaching and separating movements of both stays 51 and 52 are amplified by the X-link mechanism 4 and transmitted to the seat 2. Therefore, compared to the case where the connection point is set near the end of the link member, it is possible to move the seat 2 up and down to a greater extent with a smaller amount of operation, and good operability can be ensured.

The chair lifting device 3 also has a lower stay 5.
Since the upper stay 51 is biased by the upper end of the screw shaft 53 screwed into the screw hole 52c of No. 2, the number of parts is small, the structure is simple, and the durability can be increased. At the same time, the number of man-hours required for manufacturing can be reasonably and reliably reduced.

In addition, the cross-sectional shape of each link member and stay is
The present invention is not limited to the illustrated embodiment, and various modifications can be made without departing from the spirit of the present invention.

[Effects of the invention] Since the present invention has the above-described configuration, the following effects can be obtained.

First, in manufacturing the X-link mechanism, the left and right first link members are rigidly connected, the left and right second link members are rigidly connected in the same way, and then they are overlapped. Since each link member can be rotatably connected by crimping the fulcrum pin, manufacturing is simplified, and the distance between the link members crimped by the fulcrum pin is short and the link members can be crimped individually, making crimping easier. This can be done reliably and improves the safety at the connecting part of the link members.

In addition, when in use, the upper stay and the lower stay are moved toward and away from each other by screwing the screw shaft back and forth.
Since the link mechanism is actuated to raise and lower the seat, the raised and lowered position of the seat can be adjusted steplessly, improving the ease of use of the chair. Furthermore, since the screw type mechanism itself can have a self-locking function, it is possible to reliably prevent the inconvenience of the seat suddenly falling to the lowest position due to an erroneous operation. Therefore, the excellent effect of significantly increasing safety can be obtained without adding a separate locking mechanism that would complicate the structure and complicate operation.

Moreover, since the connection point of each stay to the link member is set in the central 1/3 area between the pivot point of the link members and the end of each link member, the bending moment acting on the stay is reduced. There is no problem that the stay becomes too large and the weight of the stay becomes large, or that the amount of relative operation of both stays becomes close to the amount of elevation of the seat and the amount of operation applied to the operating handle becomes unnecessarily large. That is, according to the present invention, it is possible to reduce the weight of the elevating device to an appropriate degree without impairing its rigidity, and it has a well-balanced structure that has good operability and allows the seat height to be adjusted relatively quickly. The chair can be provided with

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; FIG. 1 is a front view, FIG. 2 is a sectional view taken along the line -- in FIG. 1, FIG. 3 is an enlarged side view showing the main parts, and FIG. It is. 1...Chair body, 2...Seat, 3...Elevating device,
4... X link mechanism, 41... First link member, 42... Second link member, 41a... Upper end, 42a... Lower end, 43... Fulcrum pin, 51...
... Upper stay, 52 ... Lower stay, 53 ... Screw shaft, 54 ... Operation handle, a, b ... Connection point, n ... Pivot point, A, B ... Central 1/3 area.

Claims (1)

[Claims for Utility Model Registration] A chair in which a seat is supported on a chair body so that the seat height can be adjusted via an elevating device, the elevating device being connected to a first link member and a second link member along its longitudinal axis. A pair of left and right X-link mechanisms rotatably connected by fulcrum pins at the center of the direction, an upper stay installed between the corresponding first link members of both X-link mechanisms, and the upper stay. A lower stay is located below the stay and is installed between the second link members of both the X-link mechanisms, and the lower stay is screwed into a vertical screw hole provided in the lower stay, and its upper end is rotated by the upper stay. the first link member and the first link member; A connecting point of the upper stay to the first link member is set in a region of 1/3 of the center between the pivot point with the second link member and the upper end of the first link member, and a connection point between the pivot point and the second link member is set. A seat height-adjustable chair, characterized in that a connection point of the lower stay to the second link member is set in a region of 1/3 of the center portion between the link members and the lower end thereof.