Synchronization device of a chair backrest

Abstract

Synchronizing device of a chair backrest, comprising a seat body (1) which is provided on the front side with a seat support mounting section (11) and on the rear side with a backrest mounting section (13), wherein a leaf spring mounting groove (12) is located between the seat support mounting section (11) and the backrest mounting section (13), and wherein the rear groove wall of the leaf spring mounting groove (12) is arranged adjacent to the backrest mounting section (13);a seat support (2) attached to the seat support mounting section (11) of the seat body (1), wherein the seat support (2) and the seat support mounting section (11) are pivotably connected by at least one first pivot pin (21) extending therein, and wherein the rear end of a support spring tongue (22) is attached to the front of the seat support (2), and wherein the front end of the support spring tongue (22) extends to the front side of the seat support (2), and wherein at least one backrest spring leaf (24) is located in the spring leaf mounting groove (12) of the seat body (1), and wherein the front end of the backrest spring leaf (24) is connected to the rear side of the seat support (2), and wherein the rear groove wall of the spring leaf mounting groove (12) is provided with a locking section (121) which engages with the rear end of the backrest spring leaf (24). comes;and a seat plate (3) located above the seat body (1) and the seat support (2), wherein at least a second pivot pin (33) passes through the seat body (1) and the seat plate (3) to form a pivot connection, and wherein the pivot connection between the seat plate (3) and the seat body (1) is located positionally in front of the pivot connection of the seat body (1) and the seat support (2), and wherein the front end of the support spring tongue (22) of the seat support (2) rests against the front side of the seat plate (3).

Description

Technical field The invention relates to a chair, in particular a synchronizing device for a chair backrest. State of the art Various chair designs are well known. For example, document DE 101 94 640 T5 discloses a chair with adjustable seat depth, and document DE 20 2018 106 994 U1 also shows an adjustable chair. Publications DE 40 33 544 A1 and DE 44 21 597 A1 describe conventional office chairs with a spring mechanism, and document DE 10 2013 017 312 A1 describes a chair suitable for prolonged sitting. Furthermore, publication DE 20 2019 106 079 U1 discloses an armchair that can be operated smoothly and stably. Publication EP 1 946 676 B1 also discloses a chair that includes a seating mechanism allowing the seat to swivel laterally. Furthermore, a synchronous mechanism for a seat and backrest is known from publication TW M599751 U, while a chair capable of swiveling forwards and backwards is known from publication CN 215271602 U. When the user sits on these chairs and leans against the backrest, causing it to change its angle, the seat can swivel synchronously to create a synchronous pivoting motion. This results in a more comfortable sitting posture. However, the synchronous mechanism between the seat and backrest of the conventional chair is too complex in its structural design, has too many components, requires relatively high manufacturing costs, and takes up a lot of space, which detracts from the overall aesthetics of the chair. Object of the invention The invention is based on the objective of creating a synchronous device for a chair backrest with a simple construction, low manufacturing costs and a flat design in volume, by which the seat can be moved in sync with the seat plate. Technical solution This problem is solved according to the invention by a synchronizing device for a chair backrest, which has the features specified in claim 1. Further advantageous embodiments of the invention are described in the dependent claims. The inventive synchronizing device for a chair backrest offers, for example, the following advantages: 1. The inventive synchronizing device for a chair backrest has the advantages of a simple construction, low manufacturing costs, and effective use of the interior space of the seat to achieve the flattening of the overall structure according to the invention. Furthermore, the inventive synchronizing device for a chair backrest has a very attractive appearance and can therefore improve consumer purchasing intentions, thereby enhancing the industrial competitiveness of the present invention. 2. When the user leans back against the inventive backrest, the body of the user sitting on the seat is pushed upwards in unison.This utilizes the force of the user lying on the seat back to support the user's body weight on the seat, thus achieving a self-supporting effect. 3. According to the invention, a connecting strip is arranged between the seat plate and the support spring tongue, forming an enclosed angle of approximately 6 degrees between the connecting strip and the seat plate. This allows the upholstered seat to be tilted forward by 6 degrees when the user is seated on it, thereby improving seating comfort. Brief description of the drawings The invention will now be explained in more detail with reference to an embodiment illustrated in the drawings. The drawings show: Fig. 1 a perspective view of the construction according to the invention; Fig. 2 a section I through the construction according to the invention; Fig. 3 a section II through the construction according to the invention; Fig. 4 a partially enlarged cross-sectional view I of the construction according to the invention; Fig. 5 a partially enlarged cross-sectional view II of the construction according to the invention; Fig. 6 a partially enlarged cross-sectional view of the seat according to the invention in a state in which the user is sitting on it; Fig. 7 a partially enlarged cross-sectional view of a backrest according to the invention in a state in which the user is lying down and leaning on it; Fig. 8 a partially enlarged cross-sectional view of the backrest according to the invention in a locked position; and Fig.9 a partially enlarged cross-sectional view of a height-adjustable chair column according to the invention in an actuated state. Explanation of the preferred embodiment As can be seen from Fig. 1, a synchronizing device of a chair backrest according to the invention essentially comprises a seat body 1, a seat support 2, a seat plate 3, a backrest control unit 4 and a lifting control unit 5. The seat body 1 is provided with a seat support mounting section 11 on its front side and a backrest mounting section 13 on its rear side. A leaf spring mounting groove 12 is located between the seat support mounting section 11 and the backrest mounting section 13 of the seat body 1. The rear groove wall of the leaf spring mounting groove 12 is adjacent to the backrest mounting section 13. A backrest 6 is attached to the backrest mounting section 13. As shown in Figures 2 and 3, the seat support 2 is attached to the seat support mounting section 11 of the seat body 1. The seat support 2 and the seat support mounting section 11 are pivotably connected by at least one first pivot pin 21 extending through it. The rear end of a support spring tongue 22 is attached to the front of the seat support 2. The front end of the support spring tongue 22 extends towards the front of the seat support 2, such that the support spring tongue 22 gradually curves upwards from its rear end to its front end in a curved arc. At least one seat spring leaf 23, at least one backrest spring leaf 24, and a pin 25 are located in the leaf spring mounting groove 12 of the seat body 1. In the illustrated embodiment, several seat spring leaves 23 are provided, stacked one on top of the other. The seat spring leaf 23 and the front end of the backrest spring leaf 24 are connected to the rear side of the seat support 2.The rear end of the seat spring leaf 23 is provided with a through-hole 231 through which the pin 25 passes. A stop 251 is arranged at the lower end of the pin 25, against which the base surface of the seat spring leaf 23 rests. The rear groove wall of the spring leaf mounting groove 12 is provided with a locking section 121 in the area of ​​the backrest spring leaf 24, which engages with the rear end of the backrest spring leaf 24. The groove base of the spring leaf mounting groove 12 is provided with a silencer 26 in the area of ​​the lower section of the backrest spring leaf 24, which reduces unusual noises when the seat spring leaf 23 and the backrest spring leaf 24 are actuated. The base section of the seat support 2 is provided in the center with a height-adjustable chair column 7, which is designed as an air cylinder.At the upper end of the height-adjustable chair column 7 is an operating button 71, which is located in a hollow section 27 of the seat support 2. The seat plate 3 is located above the seat body 1 and the seat support 2. The seat plate 3 is provided with a padded seat 31 on its upper surface. A pivot arm 32 is formed on the underside of the seat plate 3, on the left and right sides, with the seat body 1 being provided with a pivot section 14 on each side at the corresponding location. A second pivot pin 33 passes through the pivot section 14 and the pivot arm 32 to establish a pivot connection. The pivot connection between the seat plate 3 and the seat body 1 is located in front of the pivot connection between the seat body 1 and the seat support 2. Furthermore, the first pivot pin 21 for the pivot connection between the seat body 1 and the seat support 2 is positioned higher than the second pivot pin 33 for the pivot connection between the seat plate 3 and the seat body 1.A pin hole 36 is formed on the rear side of the seat plate 3, into which the upper end of the pin 25 of the seat support 2 engages. As shown in Fig. 4, a connecting strip 34 is arranged between the front side of the seat plate 3 and the front end of the support spring tongue 22 of the seat support 2. The connecting strip 34 is pivotally connected to the seat plate 3 and the support spring tongue 22 at the top and bottom. The connecting strip 34 is inclined from the upper rear side to the lower front side such that an included angle θ of approximately 6 degrees is formed between the connecting strip 34 and the seat plate 3. The seat plate 3 is provided with a groove 35 at its lower end face to accommodate the connecting strip 34. As shown in Fig. 5, the backrest control unit 4 has a locking pin 41 located in the leaf spring mounting groove 12 of the seat body 1. At least one locking groove 122 is formed on the rear side wall of the leaf spring mounting groove 12. In the illustrated embodiment, the locking grooves 122 are spaced apart from top to bottom on the rear side wall of the leaf spring mounting groove 12. This allows the locking pin 41 to engage in one of the locking grooves 122 as needed. A first spring element 42, designed as a tension spring, is arranged between the rear side wall of the leaf spring mounting groove 12 and the locking pin 41. A first control plate 43 is attached to one of the left and right sides of the base section of the seat plate 3. A locking element 44 is arranged between the first control plate 43 and the seat plate 3. The first control plate 43 and the locking pin 41 are connected by a first pull cord 45. The lifting control unit 5 has a second control plate 51 located on the side of the base section of the seat plate 3 opposite the first control plate 43. A second spring element 52 is arranged between the second control plate 51 and the seat plate 3. The second spring element 52 is designed as a tension spring and has a drive lever 53 located in the hollow section 27 of the seat support 2. The drive lever 53 is pivotally connected to the seat support 2. The front end of the drive lever 53 is in contact with the actuating button 71 of the height-adjustable chair column 7. The second control plate 51 and the rear end of the drive lever 53 are connected by a second pull cord 54. In use, when the user sits on the upholstered seat 31 of the chair according to the invention and the upholstered seat 31 is loaded with the user's weight, the front side of the seat plate 3 pivots downwards about the second pivot pin 33 of the seat body 1. Simultaneously, the rear side of the seat plate 3 pivots upwards. In this case, the pin 25 is pulled upwards together with the seat spring leaf 23. Using the elastic cushioning of the seat spring leaf 23, the front side of the seat plate 3 can be gradually lowered until it rests against the front end of the support spring tongue 22. As shown in Fig. 6, the connecting strip 34 engages in the groove 35 of the seat plate 3. At this point, the front side of the seat plate 3 is inclined forwards by 6 degrees to provide seating comfort for the user. Reference is made below to Fig. 7. When the user leans back on the backrest 6, the backrest mounting section 13, attached to the rear of the seat body 1, is pushed backward. Using the elastic cushioning of the backrest spring leaf 24 adjacent to the backrest mounting section 13, the backrest 6 generates an elastic pivoting motion. When the user's center of gravity shifts backward and the seat body 1, together with the seat support 2, pivots about the first pivot pin 21, the rear of the seat body 1 can be moved backward in sync with the backrest 6. At this point, the seat body 1, in front of the connection point between the seat body 1 and the seat support 2, pivots upward together with the seat plate 3 about the second pivot pin 33. The seat plate 3 is pushed upward by the pivot arms 32 arranged on both sides of the seat plate 3.This allows the user's body weight to be supported by their own strength while lying on the backrest 6, simultaneously pushing the user's body upwards. This achieves a self-supporting effect, and the synchronized movement between the backrest 6 and the seat can be used to improve the user's comfort while seated. When the user leaves the backrest 6, the deformed backrest leaf 24 returns to its original state. Simultaneously, the backrest mounting section 13, located on the rear side of the seat body 1 and intended for the backrest 6, is returned to its initial position. Referring to Fig. 8, the user can then manually pull the first control plate 43 of the backrest control unit 4, which pulls the locking pin 41 through the first pull cord 45. This engages the locking pin 41 in the locking groove 122 formed in the rear groove wall of the leaf spring mounting groove 12. This brakes the backrest mounting section 13 adjacent to the rear groove wall of the leaf spring mounting groove 12, thus keeping the backrest 6 immobile.In this way, the synchronization between the backrest 6 and the seat can be disengaged, whereby the locking element 44 located between the first control plate 43 and the seat plate 3 can be used to ensure the engagement of the locking pin 41 in the locking groove 122. After the locking action has been released by the locking element 44, the locking pin 41 is returned to its initial position by the tensile force of the first spring element 42 and thus disengaged from the locking groove 122. When the user, seated on the upholstered seat 31 of the seat plate 3, leaves the seat, the deformed seat spring leaf 23 returns to its original state, pulling downwards the pin 25 which is in sync with it. Simultaneously, the rear side of the seat plate 3, which is in sync with the pin 25, is pulled downwards. Pivoting about the point of the pivot joint between the seat plate 3 and the seat body 1, the front side of the seat plate 3 pivots upwards so that the seat plate 3 returns to a flat state. When the user wishes to adjust the seat height, the second control plate 51 of the lifting control unit 5 is actuated such that the drive lever 53 moves from the second control plate 51 via the second pull cord 54. As shown in Fig. 9, the actuating button 71 of the height-adjustable chair column 7 is pressed by the front end of the drive lever 53, causing the seat support 2 mounted on the height-adjustable chair column 7, together with the seat body 1, to undergo a height adjustment. When the user releases the second control plate 51, the front end of the drive lever 53 is moved away from the actuating button 71 of the height-adjustable chair column 7 by the elastic restoring force of the second spring element 52, which is arranged between the second control plate 51 and the seat plate 3, thus fixing the seat height after the adjustment. The above description or drawing is not intended to limit the embodiments of the present invention. According to the invention, the connecting strip 34 between the seat plate 3 and the support spring tongue 22 of the seat support 2 can be omitted, so that the front end of the support spring tongue 22 of the seat support 2 comes into direct contact with the front bottom surface of the seat plate 3.

Claims

Synchronizing device of a chair backrest, comprising a seat body (1) which is provided on the front side with a seat support mounting section (11) and on the rear side with a backrest mounting section (13), wherein a leaf spring mounting groove (12) is located between the seat support mounting section (11) and the backrest mounting section (13), and wherein the rear groove wall of the leaf spring mounting groove (12) is arranged adjacent to the backrest mounting section (13);a seat support (2) attached to the seat support mounting section (11) of the seat body (1), wherein the seat support (2) and the seat support mounting section (11) are pivotably connected by at least one first pivot pin (21) extending therein, and wherein the rear end of a support spring tongue (22) is attached to the front of the seat support (2), and wherein the front end of the support spring tongue (22) extends to the front side of the seat support (2), and wherein at least one backrest spring leaf (24) is located in the spring leaf mounting groove (12) of the seat body (1), and wherein the front end of the backrest spring leaf (24) is connected to the rear side of the seat support (2), and wherein the rear groove wall of the spring leaf mounting groove (12) is provided with a locking section (121) which engages with the rear end of the backrest spring leaf (24). comes;and a seat plate (3) located above the seat body (1) and the seat support (2), wherein at least a second pivot pin (33) passes through the seat body (1) and the seat plate (3) to form a pivot connection, and wherein the pivot connection between the seat plate (3) and the seat body (1) is located positionally in front of the pivot connection of the seat body (1) and the seat support (2), and wherein the front end of the support spring tongue (22) of the seat support (2) rests against the front side of the seat plate (3). Synchronization device of a chair backrest according to claim 1, wherein the leaf spring mounting groove (12) of the seat body (1) further accommodates at least one seat leaf (23) and a pin (25), wherein the front end of the seat leaf (23) is arranged on the rear side of the seat support (2), and wherein the seat leaf (23) is provided on its rear side with a through-hole (231) through which the pin (25) passes, and wherein a stop (251) is arranged at the lower end of the pin (25) against which the bottom surface of the seat leaf (23) rests, and wherein the upper end of the pin (25) is attached to the rear side of the seat plate (3), and wherein a connecting strip (34) is arranged between the front of the seat plate (3) and the front end of the support spring tongue (22) of the seat support (2), the connecting strip being connected at the top and bottom to the seat plate (3) and the support spring tongue (22). It is connected in a swiveling manner. Synchronizing device of a chair backrest according to claim 2, in which the connecting strip (34) is inclined from the upper rear to the lower front such that the connecting strip (34) forms an angle (θ) with the seat plate (3). Synchronizing device of a chair backrest according to claim 3, in which the angle (θ) between the connecting strip (34) and the seat plate (3) is 6 degrees. Synchronizing device of a chair backrest according to claim 2, in which the seat plate (3) is provided at the bottom of the front face with a groove (35) for receiving the connecting strip (34). Synchronizing device of a chair backrest according to claim 1, in which the support spring tongue (22) gradually extends upwards from its rear end to its front end in a curved arc shape. Synchronizing device of a chair backrest according to claim 1, in which a pivoting tube (32) is formed on the underside of the seat plate (3) on the left and right, wherein the seat body (1) is provided with a pivoting section (14) on the left and right at the corresponding location, and wherein the second pivot pin (33) passes through the pivoting tube (32) of the seat plate (3) and the pivoting section (14) of the seat body (1) to establish a pivot connection. Synchronizing device of a chair backrest according to claim 1, in which the groove base of the leaf spring mounting groove (12) in the area of ​​the lower section of the backrest leaf spring (24) is provided with a silencer piece (26). Synchronization device of a chair backrest according to claim 1, further comprising a backrest control unit (4) having a locking pin (41) arranged in the leaf spring mounting groove (12) of the seat body (1), wherein at least one locking groove (122) is formed on the rear groove wall of the leaf spring mounting groove (12) into which the locking pin (41) engages, and wherein a first control plate (43) is attached to one side of the seat plate (3), and wherein the first control plate (43) and the locking pin (41) are connected to each other. Synchronizing device of a chair backrest according to claim 1, further comprising a lifting control unit (5) comprising a second control plate (51) attached to one side of the seat plate (3), wherein the second control plate (51) comprises a drive lever (53) connected to the second control plate (51), wherein a hollow section (27) is formed in the seat support (2) in which the drive lever (53) is located and pivotably connected to the seat support (2), wherein the seat support (2) is provided on its bottom side with a height-adjustable chair column (7) having an actuating button (71), wherein the upper end of the height-adjustable chair column (7) is located in the hollow section (27) of the seat support (2), and wherein the front end of the drive lever (53) is in contact with the actuating button (71) arranged at the upper end of the height-adjustable chair column (7).

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