# US 12,178,324 B2 · Synchronous mechanism for a piece of seating furniture, and piece of seating furniture > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,178,324 B2 - Document ID: US12178324B2 - Status: Granted - Kind: B2 - Application number: 17/309,257 - Filed: 2019-11-18 - Published: 2024-11-21 - Granted: 2024-12-31 - Earliest claimed: 2018-11-20 - Assignees: Comfordy Co., Ltd. - Applicants: Comfordy Co., Ltd. - Inventors: Armin Sander; Martin Potrykus - Web page: https://patentgrep.com/patent/US12178324B2 ## CPC - A47C 1/03277: {with bar or leaf springs} - A47C 1/03255: {with a central column, e.g. rocking office chairs} - A47C: CHAIRS; SOFAS; BEDS ## Abstract A synchronous mechanism for a seating furniture is provided having a seat surface support, a bending element whose length in the sagittal direction extends over a large part of a seat depth of the seat surface support and is coupled to the seat surface support for movement relative thereto. The synchronous mechanism has a backrest support mounted movably relative to the bending element for holding a backrest. The backrest support merges at the end into a pivot lever, coupled to the bending element at a pivot point to be pivotable about an axis of rotation transverse to the sagittal plane, a lever section of the pivot lever is in contact with the seat surface support at a bearing point, and, in the unloaded state of the seating furniture, the pivot point lies higher than the bearing point, as seen in the vertical direction. ## Claims ### Claim 1 A synchronous mechanism (18) for a seating furniture (1), for a chair, with a seat surface support (4) for supporting a seat surface (2) in an intended final assembly state of the seating furniture (1), with a bending element (20), the length of which extends in sagittal direction (30) over a major part of a seat depth of the seat surface support (4), and which is movably coupled to the seat surface support (4) with respect thereto, with a backrest support (16) for supporting a backrest (14), said backrest support being mounted movably relative to the bending element (20), wherein the backrest support (16) merges at an end into a pivot lever (32) which is coupled to the bending element (20) at a pivot point (34) so as to be pivotable about an axis of rotation transverse to the sagittal plane, wherein a lever section (38) of the pivot lever (32) is in contact with the seat surface support (4) at a bearing point (40), and wherein, an unloaded state of the seat furniture (1), the pivot point (34) lies higher than the bearing point (40) when viewed in the height direction. ### Claim 2 (depends on 1) The synchronous mechanism (18) according to claim 1, wherein the bending element (20) has a receptacle for a frame (8) of the seating furniture (1). ### Claim 3 (depends on 1) The synchronous mechanism (18) according to claim 1, wherein in the unloaded state the bearing point (40) is arranged such that a movement vector (B) is aligned parallel to a vertical axis or inclined at an acute angle away from the vertical axis and the pivot point (34). ### Claim 4 (depends on 1) The synchronous mechanism (18) according to claim 1, wherein the bending element (20) is divided by the pivot point (34) and/or the bearing point (40) into a short spring arm facing a rear side of the seat surface support (4) and into a long spring arm elongated in comparison to the short spring arm and facing a front side. ### Claim 5 (depends on 1) The synchronous mechanism (18) according to claim 1, wherein the bending element is designed as a leaf spring (20). ### Claim 6 (depends on 1) The synchronous mechanism (18) according to claim 1, wherein the lever section (38) of the pivot lever (32) is in unattached contact with the seat surface support (4) at the bearing point (40). ### Claim 7 (depends on 6) The synchronous mechanism (18) according to claim 6, wherein the lever portion (38) of the pivot lever (32) is arranged to be displaceable relative to the seat surface support (4) while varying a lever length. ### Claim 8 (depends on 1) The synchronous mechanism (18) according to claim 1, wherein the bending element (20) is form-lockingly held on at least one of a front and a rear edge region (42, 44) of the seat surface support (4) so as to be displaceable parallel to the sagittal direction (30). ### Claim 9 (depends on 1) The synchronous mechanism (18) according to claim 1, wherein the bending element (20) is coupled to the seat surface support (4) at at least one of a front and a rear edge region (42, 44) of the seat surface support (4) by means of a corresponding pivot bearing (46, 48). ### Claim 10 (depends on 9) The synchronous mechanism (18) according to claim 9, wherein the bending member (20) is coupled to the seat surface support (4) at both the front and rear edge regions (42, 44) of the seat surface support (4) by means of the corresponding pivot bearing (46, 48), and wherein the lever portion (38) of the pivot lever (32) is coupled to the scat surface support (4) at the bearing point (40) by means of a pivot bearing (54). ### Claim 11 (depends on 1) The synchronous mechanism (18) according to claim 1, wherein the bending element (20) and the seat surface support (4) are formed in a one piece formation as legs of a leaf spring (20) which are formed by slots (52), wherein the legs are movable relative to one another. ### Claim 12 (depends on 11) The synchronous mechanism (18) according to claim 11, wherein the bending element (20) and the seat surface support (4) are formed monolithically. ### Claim 13 (depends on 1) The synchronous mechanism (18) according to claim 1, wherein the bending element is a leaf spring (20) formed by of a fiber-reinforced polyamide plastic composition. ### Claim 14 (depends on 1) A seating furniture (1) with a synchronous mechanism (18) according to claim 1.