Abstract: The invention relates to a load-bearing frame for a chair, in particular for an office chair, which can be adjusted in terms of its height and inclination and comprises a seat carrier (1), a backrest carrier (2), a load-bearing and pivoting device (80) and a standing column (5). By means of struts (46, 32) arranged on the knee side and backrest side and supported on a spindle body, the seat carrier and backrest carrier (1, 2) are mounted on a spindle body such that they can pivot about a horizontal axis (X), oriented transversely to the seat direction, against the restoring force at least of a first spring element (40, 40'), and, in any position, can be fixed, and released again, by a second spring element.

Abstract: There is proposed a chair, particularly an office chair, of adjustable height and inclination which has a seat support (75), a backrest support (80), a standing column (10) with first gas spring (20) arranged therein, a support member (25) arranged in horizontal plane on the standing column (10), and a first guide rod (65) and a second guide rod (70). The second guide rod (70) is mounted with two struts laterally on the support member (25) and is functionally connected with a transmission mechanism.

Abstract: An adjusting mechanism for an adjustable chair includes a control mechanism, by means of which a control push rod of a spring mechanism is adjusted from a locking position to an unlocking position. In the unlocking position, the chair frame which comprises a seat carrier, a back rest carrier and a pedestal constituted by a pillar and a support part, can undergo a positional adjustment. The locking and unlocking positions are set with a single handle of an operating member which effects a displacement of two control bolts provided with meshing tooth systems, which makes the adjusting mechanism simpler and more advantageous to use.

Abstract: A chair frame comprises a seat part and a backrest part. A spring connecting portion, which is fixed by a pivot joint to the free end of a support arm is provided at the knee side of the seat part. To the backrest part is fixed at least one backrest strut, which is mounted by means of a pivot joint on a slide, which is displaceably guided in the support arm. A compression spring is mounted in the support arm. One end of the compression spring is connected to the slide while its other end is mounted by means of a pivot joint in the side walls of the support arm. A lever is connected to the spring connection portion at the knee side. An adjusting screw is connected to the lever. The adjusting screw adjusts the bias of the knee side spring portion of the seat part.

Abstract: The adjusting mechanism is used for exerting a force on two components moveable relative to one another and comprises a cylinder, a piston and a piston rod. A guide rod is also provided on the piston and is guided in a guide connection of a bottom cylinder casting. A control piston is displaceably guided in a longitudinal bore of the piston and in a further longitudinal bore of the guide rod. The piston contains transfer ducts, which are either obturated by the control piston or are freed or exposed by a smaller diameter portion of the control piston. An inner cylinder chamber is completely filled with a flowable or fluid grease. As a result, the piston rod can be locked in position by the control piston closing the transfer ducts and, on releasing or opening the latter, the piston rod can be moved. The locking of the adjusting mechanism in a specific position, as is particularly required in the case of tiltable chairs, is consequently facilitated in comparison to known adjusting mechanisms.

Abstract: The adjusting device possesses a hydraulic cylinder in whose cylinder tube there are housed a main piston equipped with a piston rod, an auxiliary piston and a force-exerting spring. The cylinder tube is closed off at both of its ends by an associated end flange. The outer surface of the cylinder tube simultaneously constitutes the guide surface of a guide tube which is fixedly connected by means of a connecting flange with the piston rod. Since the cylinder tube possesses an essentially constant or uniform inner diameter and outer diameter, the guide tube can be constructed to be so long that the adjusting device is stable enough to serve as a supporting column or pillar, e.g. for a chair or other seat structure.

Abstract: The chair has a seat or seat portion equipped with a balance and its linkage structure has links fixed in articulated manner to a support arm and to which there is articulated a balance device in parallelogram-like manner. A slide is slidingly guided on the balance device and is connected by means of a thrust rod to an extension arm of the backrest-side link. The slide is also connected to one end of a spring element, the other end of which is supported on the balance device. The linkage structure is supported on the backrest by means of a backrest strut articulated to the slide. The seat and backrest portions of the chair frame can be constructed as a plastic shell with a knee-side bending joint and a further bending joint between the seat portion and the backrest portion.

Abstract: The chair support comprises a supporting structure, a seat holder and a backrest holder. The seat holder is connected by means of a first swivel joint with the supporting structure and by means of a second swivel joint with the backrest holder. At an arm or arm structure of the backrest holder extending in a direction towards the front end of the chair support where the seat user's legs will fit, a guide rod or link and the piston rod of a spring element are rotatably mounted by means of a third swivel joint, while at the other end of the chair support, the spring element is mounted by means of a holding bracket at a swivel joint supported in the supporting structure. At the spring element, there is provided an operating slide tappet or plunger for alternately blocking and allowing free movement of the spring element, which is operable by means of an operating or actuating mechanism composed of a rod and a two-armed angle lever mounted in the holding bracket and by means of an adjusting lever.

Abstract: The chair support comprises a supporting structure, a seat holder and a backrest holder. The seat holder is pivotably or swivelably connected by means of a first swivel joint with the supporting structure and by means of a second swivel joint with the backrest holder. The backrest holder possesses an arm or arm structure and a substantially flat-surfaced hollow tube which is fitted and fastened in a holding support of the arm. The arm or arm structure projecting into about the middle of the chair support between the first and the second swivel joint is connected with a third swivel joint by means of guide rods or links which are supported at the supporting structure by means of a fourth swivel joint. A first spring element engages at the third swivel joint and a second spring element engages at the supporting structure. Both spring elements are releasable and blockable by means of operating or actuating rods.

Abstract: A seat carrier and a back rest carrier are linked by pivot joints through a lever to a carrying or swivelling component. At the end of the seat carrier on the back rest side there is connected a chain of link members which at its other end is connected to a slide and a back rest. When the chair inclines towards the rear, the chain of link members causes the slide and the back rest to conjointly move in a downwards direction. The so-called undressing effect caused by the change-over from the normal position into the rearwardly inclined position of the back rest is eliminated in a simple and space saving manner and without exploiting the space below the seat carrier. By arranging a spring element, for instance a gas spring, in the knee region of the chair, ready access can be had to the spring element for arresting it.

Abstract: The seat member and the back member are adjustably mounted at each side of the chair in two support bearings or pivot joints of a chair base and are connected to one another by a third pivot joint. The seat member comprises an extension in the direction of the back member while the back member is maintained in spaced relationship to the third pivot joint by part of a lower strut portion on each side of the chair. A spring element is mounted at its ends on the free end of the extension part of the seat member and on the back member. In transition from the working position (full lines) into the relaxed or reclined position (broken lines), a relative motion is superimposed upon the pivoting motions of the seat member and of the back member. This relative motion produces unequal vertical downward displacements of the free end of the seat extension and of the backrest portion where it joins the strut portion.

Abstract: A reclining chair is disclosed containing a conventional seat portion pivotable about a fixed pivot shaft or axle and a backrest containing a backrest plate displaceable upon guide rails. These guide rails are pivoted to a greater extent than the seat during the rearward reclining of the seat, due to the action of a guide element connected with a piston rod of a pneumatic spring arrangement. Due to the movement of the guide element there is rotated a transmission lever pair about a stationary pivot shaft, the transmission lever pair being connected with the guide element. A curved entrainment member, hingedly connected with this transmission lever pair, is connected with the backrest plate. Since a pivot shaft between the transmission lever pair and the curved entrainment member moves through an appreciably larger distance than the connection location between the seat and the guide element or the guide rails, the backrest plate is downwardly drawn along the guide rails.

Abstract: A ball locking mechanism for the releasable locking of a movable part comprises a locking or arresting ball arranged in at least one bore of a stationary or fixed part or component and can be pushed, by means of a slide member, into one of a number of bores of the movable part or element, so that such movable part can be locked in place. For unlocking, the slide member is displaced until a bore thereof comes to lie essentially coaxially with respect to the remaining bores. Then, the ball moves out of the aforementioned one bore of the movable part. The movable part can then be displaced until a further similar bore thereof comes to lie essentially coaxially with respect to the bore of the fixed part. By means of the pressure of a spring, exerted upon the slide member, the ball then is again pushed into this further bore.