JP7489187B2 - Chair with torsion spring - Google Patents

Description

The present invention relates to a chair equipped with a torsion spring that uses the repulsive force (hereinafter also referred to as spring force) of a torsion spring to change the position of a seat body, which has a seat surface and a backrest, from a seated position (position when in use) approximately parallel to the floor surface to an upright position (position when not in use) and can be stacked (hereinafter also referred to as nesting) in the front-to-back direction on the floor surface.

Conventionally, there are chairs that can be stacked vertically or nested front to back when not in use, thereby reducing the footprint they take up when not in use and improving space efficiency when stored.

As for nesting chairs, chairs equipped with torsion springs that use spring force to raise the seat are known from Patent Documents 1 to 3, etc.

In known chairs, the use of torsion springs requires that the seat be kept in a reclined position roughly parallel to the floor when in use, in order to keep the seat upright using only spring force. Some known chairs keep the seat in a reclined position when the user is seated.

Patent No. 3321727 Japanese Utility Model Publication No. 64-128 Patent No. 6527623

The present invention aims to provide a nesting chair that uses the spring force of a torsion spring to raise the seat, does not use a locking mechanism to keep the seat in a reclined position, and is equipped with a torsion spring that does not force the seat occupant to remain in a reclined position.

The configuration of a chair equipped with a torsion spring of the present invention, which has been made to solve the above problems, is as follows:
A chair equipped with a torsion spring, the torsion spring comprising a seat cover having a seat body with a seat surface and a backrest on its upper surface, a bracket to which the seat cover is rotatably connected via a torsion spring and a support shaft between a lying position approximately parallel to the floor and an upright position at a desired angle, and legs including a cross member having a support portion supporting the bracket and the seat cover in the lying position, characterized in that the repulsive force of the torsion spring is adjusted so that the repulsive force of the seat body is approximately balanced with the load acting on the torsion spring at a position (hereinafter referred to as the intermediate position) between the lying position when the seat body including the seat cover is not in use and the lying position when in use, and including both the position before and the position after that.

When the seat body, including the seat support cover, is pushed in the upright direction with a hand placed on it at an angle approximately halfway between the upright angle and the collapsed angle, it stands up, and when pushed in the collapsed direction, the seat body's own weight overcomes the repulsive force of the torsion spring and collapses, so there is no impact at the upright end and collapsed end, and the movement is gentle.

The chair has a seat cover with an insertion hole at the front end of the upper surface of the approximately dish-shaped body into which the front end of the bracket fits, and a stopper wall with an axial hole that acts on the bracket erected beside the insertion hole to prevent the seat cover from rotating in the upright direction at the upright angle set for the seat body, the bracket that fits into the insertion hole has a bearing at its tip coaxially with the axial hole of the stopper wall, the seat cover and bracket are connected by passing the support shaft that supports the torsion spring through the axial hole and the bearing, and a rotation restriction mechanism is provided in which, when the seat cover rotates from the lying down position to the upright side, the stopper wall comes into contact with the bracket to prevent the upright rotation of the seat cover at the upright angle set for the seat body.

The seat cover and the support part can be provided with a contact retaining member on the seat cover or on the support part with which the seat cover contacts, and the contact retaining member can assist in maintaining the state in which the seat cover contacts the support part at the end of the downward rotation of the seat body including the seat cover.

In the present invention, the support part can be made of steel, and the seat cover can be configured to have a magnet as a contact holding member at the part that contacts the support part. The magnet is provided on the seat cover in a non-contact state with the support part, so that there is no metallic sound when it contacts the support part, and the magnet does not hit the support part and damage the paint film.

The rotation restriction mechanism is formed by the structure of the connected seat cover and bracket, so no separate, dedicated parts are required. Therefore, the structure of the rotation restriction mechanism is simple, easy to assemble, and unlikely to break down. The leg frame of the chair can be configured in such a way that two leg frames with different widths when viewed from the front are joined by the horizontal member so that they form a roughly inverted V shape when viewed from the side.

The seat cover and the bracket can be provided with an abutment support member on the stopper wall or on the seat cover and the support part with which the stopper wall abuts, so that the abutment retaining member can maintain the state in which the seat cover abuts on the support part at the end of the downward rotation of the seat body including the seat cover.

In addition, by providing a click member on the bracket that resiliently engages with the seat cover at the end of the seat body's upright rotation, the end of the seat cover can be felt with a clicking sensation and held in the end position by the click member resiliently engaging with the seat cover.

The bracket is attached to the connected horizontal member, and is installed at two locations near the center of the horizontal member where both ends of the support shaft that supports the torsion spring correspond. As a result, the connection part with the seat cover is located approximately in the center of the horizontal member. The bracket is formed of a tube having two vertical walls with spaced-apart tips, and bearings for the support shaft are provided in the two vertical walls. The tube of the bracket acts as a regulating wall for the stopper wall that rotates upright, the upper wall of which is

The support walls on the seat cover are erected on the left and right of the bracket insertion hole on the seat cover, and are positioned to sandwich the tip of the bracket inserted from below into the insertion hole. The stopper wall of the seat cover is positioned between the two erect walls at the tip of the bracket.

The torsion spring is installed on the seat cover with high stability because the support shaft inserted into the coil portion passes through the shaft holes in the support wall and stopper wall of the seat cover and the bearing of the bracket. One end of the torsion spring is detachably fixed to the fixed system of the leg including the bracket, and the other end is detachably fixed to the movable system of the seat cover. The spring force (repulsive force) of the torsion spring can be adjusted by changing the fixed position of the fixed system around the support shaft to adjust the spring force (repulsive force) acting on the seat body. The support shaft of the torsion spring is supported by multiple sets of shaft holes and bearings, making the connection between the seat cover and the support shaft of the bracket via the torsion spring high strength and high stability.

In the present invention, the spring force of the torsion spring is adjusted to be in balance with the load of the seat body acting on the torsion spring in the intermediate position (intermediate position between the upright angle and the collapsed angle) between the upright position (upright angle) and the collapsed position (collapsed angle). Therefore, from the intermediate position toward the upright end, the load against the spring force of the seat body 1, whose position changes as it stands up, gradually decreases, and the seat body reaches the upright end with the spring force. On the other hand, from the intermediate position where the spring force and the load of the seat body are in balance toward the collapsed end, the load against the spring force gradually increases as the seat body collapses to the horizontal side, so the seat body reaches the collapsed end under its own weight while receiving the cushioning effect of the spring force. In the present invention, the spring force is adjusted so that the load of the seat body and the spring force of the torsion spring are in balance in the middle of the seat body's rise and fall range, so the seat body does not move suddenly, but moves gently supported by the spring force.

FIG. 1 is a perspective view of an example of a nestable chair of the present invention. FIG. 2 is a front view of the chair of FIG. 1. FIG. 2 is a rear view of the chair of FIG. FIG. 2 is a right side view of the chair of FIG. 1. FIG. 2 is a bottom view of the chair of FIG. FIG. 6 is a right side view of the chair shown in FIGS. 1 to 5 with the seat upright. 13 is a side view showing the relationship between the support portion of the seat support cover and the cushioning member during nesting. FIG. FIG. 7 is an enlarged cross-sectional view of part A in FIG. 6 . 6 is an enlarged plan view of the chair of FIG. 1 to FIG. 5 with the seat body removed to show the seat support cover. FIG. 10 is a bottom view of the seat support cover of FIG. 9 . FIG. FIG. 12 is an exploded perspective view of the seat support cover of FIG. 11 . 13 is an enlarged side view showing a schematic diagram of a relationship between a stopper wall and a bracket of a connecting mechanism between the seat receiving cover and the bracket. FIG.

Next, an embodiment of a chair according to the present invention will be described with reference to the drawings.
In the drawings, reference numeral 1 denotes a seat body having a seat surface 1a and a backrest 1b, and in the drawing, the bottom surface 1a and the backrest 1b are made of a synthetic resin molded body. The structure of the seat body 1 is not limited to the example shown in the drawing, and may be of another form as long as the seat surface 1a and the backrest 1b are integrated.

2 is a seat cover formed of a shallow dish-shaped body with the seat body 1 removably installed on the upper surface. As shown in Fig. 7 in a plan view and in Fig. 8 in a bottom view, the seat cover 2 has two insertion holes 2a, which are approximately rectangular in plan view, near the center of the front end, into which the bracket 3 described later enters from below. On the upper surface of the seat cover 2, two support walls 2b are provided that sandwich each insertion hole 2a from the left and right, and two stopper walls 2c are sandwiched between the two support walls 2b. The support walls 2b and the stopper walls 2c are integrally molded with the seat cover 2. The support walls 2b and the stopper walls 2c are provided with an axis hole Sh through which the support shaft 7 described later passes, and the bearing Sb provided at the tip of the bracket 3 corresponds to the axis of this axis hole Sh. 2e are bolt holes or other attachment points for the seat body 1 or the seat surface (not shown) that is separate from the backrest, and are provided at four locations near the outer periphery of the seat cover. When removing the chair seat body 1 to perform maintenance on the internal rotation mechanism of the seat cover 2, the bolt holes 2e must be used, so the seat cover 2 must be held in a collapsed position. To keep the seat cover 2 in a collapsed position, two jig holes 2f are provided in the front of the seat cover 2. When a pin-shaped jig member (not shown) is inserted into these jig holes 2f, even if the seat cover 2 tries to stand up, the jig member hits the buffer member 9 provided on the horizontal member 4b (described later) and prevents the seat cover 2 from standing up and rotating, so the seat cover 2 can be held in a roughly horizontal position for maintenance work.

With the above-mentioned configuration of the seat support cover 2 and bracket 3, the components that make up the connection between the seat support cover 2 and bracket 3, which raises and lowers the seat body 1, are all contained within the space formed by the upper surface of the seat support cover 2 and the lower surface of the seat body 1, and the connection mechanism and rotation restriction mechanism are not exposed to the outside.

4 and 5 are two leg frames that are roughly gate-shaped when viewed from the front, with horizontal members 4a and 5a that are roughly parallel to the floor on top of left and right vertical members 4b and 5b, and the left and right widths of the left and right vertical members 4b of the leg frame 4 on the near side (front) when viewed from the front are larger than the left and right widths of the left and right vertical members 5b of the leg frame 5 on the far side (rear). The two leg frames 4 and 5 are integrated with their horizontal members 4a and 5a overlapping in the front-to-rear direction to form the legs.

The combined front and rear leg frames 4, 5 have vertical members 4b, 5b that are formed in a roughly inverted V shape when viewed from the side. With this configuration, when the chair of the present invention is viewed from the perspective of a person standing in use, only the front and rear leg frames 4, 5 appear to extend diagonally downward from a single point on the underside of the seat support cover 2, which is a distinctive design feature.

Two brackets 3, 3 are provided in parallel with each other near the center of the integrated horizontal members 4a, 5a of the leg frames 4, 5, protruding toward the front of the seat cover 2, and a support part 6 that is approximately U-shaped in plan view is provided facing the opposite direction to the brackets 3. The support part 6 is a member that supports the lying position of the seat body 1 from below. The horizontal members 4a, 5a are provided with a buffer member 9 that abuts against the support part 6 of the front chair when nesting. The installation position of this buffer member 9 can be the center of the support part 6 or the underside of the seat cover 2, not shown, instead of the horizontal members 4a, 5a. When the buffer member 9 is provided on the underside of the support part 6 or the seat cover 2, it buffers the tip of the rear chair that is nested. The buffer member 9 of the seat cover 2 is integrally molded when the seat cover 2 is a resin molded product. 4c, 5c are casters provided at the lower end of the leg frames 4, 5.

The seat cover 2 and bracket 3 have a coaxial shaft hole Sh in the support wall 2b and stopper wall 2c that are integrally molded on the seat cover 2, and the left and right brackets 3 exposed on the upper surface side of the seat cover 2 from the two insertion holes 2a of the seat cover 2 have bearings Sb coaxial with the shaft hole Sh. When the support shaft 7 is placed through the shaft hole Sh and bearing Sb, the seat cover 2 and bracket 3 are connected to each other so that they can rotate freely.

The support shaft 7 is inserted into the coil portion of the torsion spring 8, so that the torsion spring 8 is arranged together with the support shaft 7 at the front end of the seat support cover 2. One end 8a of the arranged torsion spring 8 is fixed to the movable system of the seat support cover 2, and the other end 8b is fixed to the fixed system of the leg frames 4, 5 including the bracket 3. 81a is a fixing member for fixing the one end 8a to the seat support cover 2. Note that the fixing member 81a is attached by pressing one end 8a of the torsion spring 8 against the underside of the seat support cover 2 with a screw 81b, so that it is virtually impossible for one person to press the fixing member 81a and tighten the screw 81b. However, if the front end of the fixing member 81a can be hooked to a locking portion (not shown) on the seat cover 2 so that it can be supported, assembly becomes easier because the front end of the fixing member 81a can be hooked to the locking portion and the fixing member 81a can be held down with one hand while the screw 81b can be tightened with the other hand. The torsion spring 8 biases the bracket 3 and seat cover 2, which are rotatably connected by the support shaft 7, in the direction that raises the seat cover 2.

In the present invention, the upright angle of the seat body 1 is set, for example, in the range of 60 degrees to 30 degrees, preferably 45 degrees to 35 degrees. In this setting, the repulsive force (spring force) of the torsion spring 8 is adjusted so that the seat body 1 at the midpoint between the tilt angle and the upright angle of the seat body 1 is approximately balanced with the load acting on the torsion spring 8. If the spring force is approximately balanced with the load of the seat body 1 at the approximately midpoint, when the seat body 1 is in a tilted position (approximately parallel to the floor), the spring force of the torsion spring 8 becomes smaller than the load of the seat body 1 acting on this torsion spring 8 (the balance between the load of the seat body 1 rotating in the tilted direction and the spring force is lost), so the seat body 1 rotates in the tilted direction under its own weight and reaches the tilt end, and the tilted position can be maintained without the need for a locking mechanism.

In the present invention, the load of the seat body 1 acting on the torsion spring 8 and the repulsive force of the torsion spring 8 are balanced at an angle intermediate between the upright angle and the downright angle of the seat body 1. Therefore, the load on the spring force of the seat body 1 gradually decreases during the upright movement from the intermediate position to the upright end, and the seat body 1 rises gently. The upright end is determined when the upper surface 22c of the stopper wall 2c provided on the seat support cover 2 abuts against the upper wall 3a of the inner surface of the bracket 3, and the seat body 1 is held in that position by the spring force. On the other hand, the seat body 1 falls gently because the load on the spring force of the seat body 1 gradually increases from the intermediate position onwards. The downright end is determined when the abutment part 21 provided on the lower surface 2d of the seat support cover 2 abuts against the upper surface 6a of the support part 6 provided on the leg frame 4, 5, and the seat body 1 is held in that position by its own weight.

In the chair of the present invention, the spring force of the torsion spring 8 is adjusted to be in balance with the load of the seat body 1 acting on the torsion spring 8 in the intermediate position (angle at the intermediate position between the standing angle and the collapsed angle) between the standing position (standing angle) and the collapsed position (collapsed angle). As a result, the load on the spring force of the seat body 1, which changes its position as it stands up, gradually decreases from the intermediate position toward the standing end, so that the seat body 1 reaches the standing end with the spring force. On the other hand, from the intermediate position where the spring force and the load of the seat body 1 are in balance toward the collapse end, the seat body 1 falls to the horizontal side and the load on the spring force gradually increases, so the seat body 1 reaches the collapse end under its own weight while receiving the cushioning effect of the spring force. In this way, the seat body 1 performs a gentle rise and fall movement because the spring force is adjusted to be in balance with the load of the seat body at the intermediate position of its rise and fall range.

The rising end of the seat body 1, which rises gently as described above, can be detected by the abutment of the stopper wall 2c and the bracket 3 (the upper surface 22c of the stopper wall 2c abuts the upper wall 3a of the bracket 3). As an example, as shown in FIG. 11, if a click member 3b having a protrusion 33b that resiliently engages with the seat cover 2 in the rising end position is placed on the bracket 3, the protrusion 33b resiliently engages with the seat cover 2 at the rising end of the seat body 1, so that the abutment can be detected with a clicking sensation. In FIG. 11, a click member 3b in the shape of a piece having a resilient protrusion 33b is placed on the bracket 3, and when the seat cover 2 rotates to the rising end side, the edge 23c of the recess of the rising seat cover 2 repels the protrusion 33b and engages with the click member 3b, so that this series of actions allows the rising end of the seat body 1 to be detected with a clicking sensation and the rising end position to be maintained.

The end of the seat 1 can be detected by the lower surface 2d of the seat cover 2 abutting against the upper surface 6a of the support 6, and the abutting state can be maintained by the weight of the seat 1 including the seat cover 2. In order to detect this end of the seat 1 with a clicking sensation, for example, a synthetic resin abutment 21 having a magnet 21a as an abutment holding member can be provided on the lower surface 2d of the seat cover 2 facing the upper surface 6a of the support 6. In this way, when the abutment 21 of the seat cover 2 abuts against the support 6, the magnet 21a attracts the support 6, so that the end of the seat 1 can be detected with a clicking sensation by the magnetic attraction sensation, and the seat 1 can be held in that position. The magnet 21a can be provided on the surface or inside of the abutment 21, or the abutment 21 itself can be formed of a magnet. The magnet 21a can also be provided on the side of the support 6. Also, instead of the magnet, a member that maintains the contact between the support part 6 and the seat cover 2 by frictional engagement force can be provided between the two parts 2, 6. It is preferable that the magnet 21a is provided without contact with the other side to which it is attracted. For this reason, in the example shown in Figure 8, the magnet 21a is embedded in the contact part 21 with its surface exposed.

In the nesting chair of the present invention, the load of the seat body acting on the torsion spring is balanced with the spring force of the torsion spring at the middle of the seat body's range of elevation and rotation, so that the spring force acts as a biasing force when rotating from the middle position toward the standing end side, and acts as a buffer force when rotating from the middle position toward the falling end side, allowing the seat body to rise and fall gently.

1. Seat
2 Seat cover 3 Bracket 4, 5 Leg frame 6 Support part 7 Support shaft 8 Torsion spring 9 Cushioning member

Claims (5)

A nestable chair comprising: a seat cover having a seat body having a seat surface and a backrest on an upper surface; a bracket to which the seat cover is rotatably connected between a lying position approximately parallel to the floor and an upright position at a desired angle via a torsion spring and a support shaft which fits the torsion spring externally and supports the torsion spring at a central portion in a longitudinal direction on the same axis; and legs including a horizontal member provided with a support portion which supports the bracket and the seat cover in the lying position,
The chair is characterized in that the torsion spring is a torsion spring whose repulsive force is adjusted so as to balance the load acting on the torsion spring when the seat body including the seat support cover is at an intermediate angle between an upright angle when not in use and a reclined angle when in use. The chair of claim 1, in which the repulsive force of the torsion spring is adjusted so that the seat body including the seat support cover stands up when the seat body is pushed in the upright direction with a hand placed on it at an intermediate angle between the upright angle and the repulsive angle, and the seat body collapses under its own weight, which overcomes the repulsive force of the torsion spring, when pushed in the repulsive direction. The chair of claim 1 or 2, in which the seat cover and the support part are provided with a contact retaining member on the seat cover or on the support part with which the seat cover contacts, and the contact retaining member maintains the state in which the seat cover contacts the support part at the end of the downward rotation of the seat body including the seat cover. A chair according to any one of claims 1 to 3, in which the support part is made of a magnetic material, and the seat cover has a magnet as the contact retaining member at a portion where it contacts the support part. The chair of claim 4, in which the magnet is provided on the seat cover in a non-contact state with the support part.

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