Abstract: Provided is a chair in which the rear section of the seat can be raised with good lateral balance, in which the seat is stable, and that has a simple structure and a good appearance. The disclosed chair includes a seat (6) that is pivotally attached by means of a laterally-oriented pivot shaft (9) to a support base (5) supported by (a) leg(s), the rear section of the seat (6) being pivotable in the vertical direction. In said chair, an urging means (12) that urges the seat (6) upward is constructed so as to include: an elastic expanding-and-contracting component (13) that connects a portion of the support base (5) located below the pivot shaft (9) and a portion of the seat (6) located to the rear of the pivot shaft (9); and a pair of leaf-spring-like elastic warping components (14) provided on the right and left sides of the elastic expanding-and-contracting component (13).

Abstract: Disclosed is a stretching structure of a chair upholstery material, in which an upholstery material can be easily installed in a frame body, enough deflection allowance of the upholstery material can be ensured, and further the material cost and production cost can be reduced without decreasing the strength.

Abstract: A backrest device for a chair, in which a backboard is easily flexible without a reduction in its strength, thus making the chair comfortable to sit on. The lower ends of both right and left sides of the back frame are supported at both sides at the back of a leg body, and the flexible back board is formed on the inside of rear frames. A large number of openings are formed in the backboard so as to be close to each other in the top-bottom and left-right directions. Between openings adjacent to each other in the left-right direction, there is formed a connection section continuing in the top-bottom direction, and the dimension in the front-back direction of the connection section is made larger than the dimension in the left-right direction of the connection section.

Abstract: A backrest device for a chair, capable of, without a reduction in its strength and rigidity, effectively bending backward so as to follow the shape of the back of a person seated on the chair, providing the person with excellent sitting comfort. In the backrest device, a back board is supported by a backrest frame, and the back board has a flexible back stopper on the inner side of a back frame. The thickness of a vertical intermediate section of the back stopper is gradually increased from both left and right sections of the intermediate section toward the center such that the thickness is less in both left and right sections and is maximum at the center.

Abstract: An easily operable lock device for a movable member of a chair, the lock device being adapted such that a person sitting on the chair can select lock or unlock position by operating operation means with a load, such as the weight of the person, acting on the movable member and, when the load is removed after the selection of the lock or unlock position, lock or unlock operation is executed. A lock pin provided at a spring receiving member functioning as a movable member, is selectively engaged with and disengaged from engagement holes formed in a reinforcement plate functioning as a support member. The lock device has biasing means for biasing the lock pin toward the lock position when an operation member moved by the operation means is set at a lock reservation position and biasing the lock pin toward the unlock position when the operation member is set at an unlock reservation position.

Abstract: A chair configured such that a backrest support rod does not make contact with an object when the chair is swiveled and is thus reliably prevented from damaging the object or from being damaged by the object and that the chair uses a reduced number of parts, has a simple structure, and can be easily assembled. A chair, wherein front portions of front facing sections (9b) of a backrest support rod (9) are mounted to a support base (5) supported by a leg body (3) and supporting a seat (7). The backrest support rod (9) is formed in an L-shape in a side view and comprises upwardly facing raised sections (9a) and the forwardly facing front facing sections (9b). The upwardly facing raised sections (9a) and the forwardly facing front facing sections (9b) are connected together through a curved section (9c), and the raised sections (9a) support a backrest (6).

Abstract: An upholstered structure including an upholstery material for a chair or a backrest of a chair is proposed, which may achieve: reduced proportion of the appearance of the rear frame of the backrest over the appearance of the whole chair; more sophisticated design; reduced weight; reduced number of parts; and improved assemble-ability. In the chair having the backrest upholstered with the upholstery material over the front surface of the rear frame, the rear frame comprises a front frame to which the peripheral edge part of the upholstery material is fixed and an upper reinforcement frame rod. The laterally facing upper reinforcement frame rod is connected at its both ends to both ends of the laterally facing upper frame rod at the top of the front frame with the center part of the upper reinforcement frame rod separated backward from the upper frame rod.

Abstract: A back rest tilting device in a reclining chair formed of fewer parts. A force promoting unit energizes a back rest in an upright direction. A rotating force promoting unit with rubber torsion springs includes a laterally extending pivot shaft rotated integrally with the back rest and an elastic body filled between an outer tube locked to a support body coaxially with the core and the pivot shaft so that the elastic body is elastically deformed when the pivot shaft is rotated about the center axis of the outer tube to impart a returning rotating force to the pivot shaft.

Abstract: An easily operable lock device for a movable member of a chair, the lock device being adapted such that a person sitting on the chair can select lock or unlock position by operating operation means with a load, such as the weight of the person, acting on the movable member and, when the load is removed after the selection of the lock or unlock position, lock or unlock operation is executed. A lock pin provided at a spring receiving member functioning as a movable member, is selectively engaged with and disengaged from engagement holes formed in a reinforcement plate functioning as a support member. The lock device has biasing means for biasing the lock pin toward the lock position when an operation member moved by the operation means is set at a lock reservation position and biasing the lock pin toward the unlock position when the operation member is set at an unlock reservation position.

Abstract: A backrest device for a chair, capable of, without a reduction in its strength and rigidity, effectively bending backward so as to follow the shape of the back of a person seated on the chair, providing the person with excellent sitting comfort. In the backrest device, a back board is supported by a backrest frame, and the back board has a flexible back stopper on the inner side of a back frame. The thickness of a vertical intermediate section of the back stopper is gradually increased from both left and right sections of the intermediate section toward the center such that the thickness is less in both left and right sections and is maximum at the center.

Abstract: A backrest device for a chair, in which a backboard is easily flexible without a reduction in its strength, thus making the chair comfortable to sit on. The lower ends of both right and left sides of the back frame are supported at both sides at the back of a leg body, and the flexible back board is formed on the inside of rear frames. A large number of openings are formed in the backboard so as to be close to each other in the top-bottom and left-right directions. Between openings adjacent to each other in the left-right direction, there is formed a connection section continuing in the top-bottom direction, and the dimension in the front-back direction of the connection section is made larger than the dimension in the left-right direction of the connection section.

Abstract: A stretching structure of a stretching material in a chair in which the ratio of the rear frame of a backrest to the outline of the chair is small, design is smart, weight is reduced, the number of parts is reduced, and assemblability is improved and the backrest of the chair. In the chair having the backrest formed by stretching the stretching material on the front surface of the rear frame, the rear frame comprises a front frame to which the peripheral edge part of the stretching material is fixed and an upper reinforcement frame rod. The laterally facing upper reinforcement frame rod is connected at its both ends to both ends of the laterally facing upper frame rod at the top of the front frame with the center part of the upper reinforcement frame rod separated backward from the upper frame rod.

Abstract: A back rest tilting device in a reclining chair formed of less number of parts, simple in structure, easily assembled, and well balanced in layout and energizing force. The energizing means energizing a back rest in an upright direction comprises a rotatingly energizing means with rubber torsion springs using, as a core, a laterally extending pivot shaft rotated integrally with the back rest and having an elastic body filled between an outer tube locked to a support body coaxially with the core and the pivot shaft so that the elastic body can be elastically deformed when the pivot shaft is rotated about the center axis of the outer tube to impart a returning rotating force to the pivot shaft.

Abstract: A chair has a backrest and a pair of armrests. A pair of support struts for supporting the backrest is connected to a shaft of a base under a seat. The armrest is supported by an arm post. An operating lever is mounted on the upper front end of the arm post. When the backrest is tilted, it is held at a desired angle by pressing up the operating lever.

Abstract: A chair has a backrest and a pair of armrests. A pair of support struts for supporting the backrest is connected to a shaft of a base under a seat. The armrest is supported by an arm post. An operating lever is mounted on the upper front end of the arm post. When the backrest is tilted, it is held at a desired angle by pressing up the operating lever.

Abstract: A chair has a backrest and a pair of armrests. A pair of support struts for supporting the backrest is connected to a shaft of a base under a seat. The armrest is supported by an arm post. An operating lever is mounted on the upper front end of the arm post. When the backrest is tilted, it is held at a desired angle by pressing up the operating lever.

Abstract: A chair has a backrest and a pair of armrests. A pair of support struts for supporting the backrest is connected to a shaft of a base under a seat. The armrest is supported by an arm post. An operating lever is mounted on the upper front end of the arm post. When the backrest is tilted, it is held at a desired angle by pressing up the operating lever.

Abstract: A chair has a backrest and a pair of armrests. A pair of support struts for supporting the backrest is connected to a shaft of a base under a seat. The armrest is supported by an arm post. An operating lever is mounted on the upper front end of the arm post. When the backrest is tilted, it is held at a desired angle by pressing up the operating lever.

Abstract: A power module including a self arc-extinguishing type semiconductor such as an IGBT and having a function to protect the semiconductor, i.e., to protect the IGBT against a short-circuit current. Even the IGBT having a collector-emitter saturation voltage VCE (sat) set low can be protected against the short-circuit current, by charging a collector-gate junction capacitor (13) quickly, when a sense current IS to flow through a current sense exceeds a set value, to raise a collector voltage VCE quickly thereby to prevent a collector current IC from increasing, by keeping a gate voltage VGE of the IGBT (12) at a voltage rather higher than a threshold voltage, and by turning OFF the IGBT (12) after a predetermined time.

Abstract: A chair has a backrest and a pair of armrests. A pair of support struts for supporting the backrest is connected to a shaft of a base under a seat. The armrest is supported by an arm post. An operating lever is mounted on the upper front end of the arm post. When the backrest is tilted, it is held at a desired angle by pressing up the operating lever.