Seat-backrest linkage device

Abstract

A seat-backrest linkage device includes a base, a bracket plate, a swing bracket and a connecting member. The connecting member includes a crank and a connecting plate connected as a whole. The swing bracket is provided between the base and the bracket plate. Two ends of the crank are respectively hinged to the bracket plate and the swing bracket. An slide groove guide mechanism is provided between the bracket plate and the swing bracket. The swing bracket and the base are hinged in middles, such that the swing bracket, the connecting member, and the bracket plate are capable of together tilting and swinging left and right relative to the base. The support plate seat can be raised and lowered relative to the base, and the swing bracket hinged to the base is arranged between the base and the support plate seat.

1 . A seat-backrest linkage device, comprising a base ( 1 ), a support plate seat ( 2 ) configured to support a chair seat, a swing bracket ( 3 ), and a connecting member ( 5 ) configured to connect a backrest, wherein the connecting member ( 5 ) comprises a crank ( 501 ) and a connecting plate ( 502 ) that are arranged in a front-rear direction of the base ( 1 ) and connected as a whole, the swing bracket ( 3 ) is arranged between the base ( 1 ) and the support plate seat ( 2 ), two ends of the crank ( 501 ) are respectively hinged to the support plate seat ( 2 ) and the swing bracket ( 3 ), and a slide groove guide mechanism ( 8 ) configured to guide raising/lowering of the support plate seat ( 2 ) is provided between the support plate seat ( 2 ) and the swing bracket ( 3 ); and the swing bracket ( 3 ) and the base ( 1 ) are hinged in middles, such that the swing bracket ( 3 ), the connecting member ( 5 ), and the support plate seat ( 2 ) are capable of together tilting and swinging left and right relative to the base ( 1 ). 
     
     
         2 . The seat-backrest linkage device according to  claim 1 , wherein in a front-rear direction of the base, the swing bracket ( 3 ) is of a frame structure, the swing bracket ( 3 ) comprises a front portion I ( 301 ) and a rear portion I ( 302 ) that are connected as a whole, and the base ( 1 ) comprises a front portion II ( 101 ) and a rear portion II ( 102 ) that are connected as a whole; the front portion I ( 301 ) and the front portion II ( 101 ) are rotatably connected on a left-right symmetrical centerline of the base, and the rear portion I ( 302 ) and the rear portion II ( 102 ) are rotatably connected on the left-right symmetrical centerline of the base; and the slide groove guide mechanism ( 8 ) is arranged between the front portion I ( 301 ) and the support plate seat ( 2 ), or the slide groove guide mechanism ( 8 ) is arranged between the rear portion I ( 302 ) and the support plate seat ( 2 ). 
     
     
         3 . The seat-backrest linkage device according to  claim 2 , wherein on the swing bracket ( 3 ), side wings ( 3011 ) symmetrically extend from left and right sides of the front portion I ( 301 ); on the base ( 1 ), side lugs ( 1011 ) symmetrically extend from left and right sides of the front portion II ( 101 ); and elastic mechanisms ( 4 ) configured to provide a reset force for the swing bracket ( 3 ) after swinging are symmetrically arranged on left and right sides of the chassis, and each elastic mechanism ( 4 ) is arranged between the side wing ( 3011 ) and the side lug ( 1011 ) on the same side. 
     
     
         4 . The seat-backrest linkage device according to  claim 3 , wherein the side wing ( 3011 ) and the side lug ( 1011 ) are oppositely arranged up and down, the elastic mechanisms ( 4 ) each comprise a swing pressure spring ( 401 ), and when the side wing ( 3011 ) swings along with the swing bracket ( 3 ), the swing pressure spring ( 401 ) is compressed to generate a reset elastic force. 
     
     
         5 . The seat-backrest linkage device according to  claim 4 , wherein the elastic mechanisms ( 4 ) each further comprise a bolt ( 402 ) and a nut ( 403 ); the bolt ( 402 ) oppositely passes through the side wing ( 3011 ) and the side lug ( 1011 ), and a passing part of the bolt ( 402 ) is threadedly connected to the nut ( 403 ); the swing pressure spring ( 401 ) is sleeved on a section of the bolt ( 402 ) located between the side wing ( 3011 ) and the side lug ( 1011 ), and a swing range of the swing bracket ( 3 ) is limited between the nut ( 403 ) and the side wing ( 3011 ). 
     
     
         6 . The seat-backrest linkage device according to  claim 3 , wherein in a longitudinal direction, the side wing ( 3011 ) and the side lug ( 1011 ) are each internally provided with an accommodating cavity ( 103 ) having a depth, opposite sides of the side wing ( 3011 ) and the side lug ( 1011 ) are open for communication, and upper and lower portions of the elastic mechanism ( 4 ) are respectively located in the upper and lower accommodating cavities ( 103 ). 
     
     
         7 . The seat-backrest linkage device according to  claim 3 , wherein the side lug ( 1011 ) and the side wing ( 3011 ) are oppositely arranged up and down, the elastic mechanisms ( 4 ) each comprise a tension spring, and when the side wing ( 3011 ) swings along with the swing bracket ( 3 ), the tension spring is stretched to generate a reset elastic force. 
     
     
         8 . The seat-backrest linkage device according to  claim 1 , wherein the base ( 1 ) comprises a bottom plate, side plates ( 1021 ) extending upwards from left and right sides of the bottom plate, and vertical plates ( 1022 ) extending upwards from front and rear sides of the bottom plate; the side plates ( 1021 ) are each provided with a waist-shaped hole ( 10211 ), the crank ( 501 ) is hinged to the swing bracket ( 3 ) through a first pin shaft ( 304 ), the first pin shaft ( 304 ) simultaneously passes through the waist-shaped holes ( 10211 ), and when the swing bracket ( 3 ) swings left and right, the first pin shaft ( 304 ) moves up and down in the waist-shaped holes ( 10211 ). 
     
     
         9 . The seat-backrest linkage device according to  claim 1 , wherein the swing bracket ( 3 ) is of a frame structure; the swing bracket ( 3 ) comprises left and right symmetric baffles ( 306 ), and a front surrounding plate ( 307 ) and a rear surrounding plate ( 309 ) that are connected to front and rear sides of the baffles ( 306 ); and the base ( 1 ) is located in a space enclosed by the baffles ( 306 ), the front surrounding plate ( 307 ), and the rear surrounding plate ( 309 ). 
     
     
         10 . The seat-backrest linkage device according to  claim 1 , wherein the crank ( 501 ) is in an inclined state, an upper end of the crank ( 501 ) is hinged to the support plate seat ( 2 ) through a third pin shaft ( 308 ), and a lower end of the crank ( 501 ) is hinged to the swing bracket ( 3 ) through a first pin shaft ( 304 ); the support plate seat ( 2 ) comprises a support plate ( 201 ) and hanging plates ( 202 ) hanging down on left and right sides of the support plate ( 201 );
 the slide groove guide mechanism ( 8 ) comprises a limiting slide groove ( 801 ) and a second pin shaft ( 802 ); the limiting slide groove ( 801 ) is formed in one of the hanging plate ( 202 ) and the swing bracket ( 3 ), the second pin shaft ( 802 ) is connected to the other one of the hanging plate ( 202 ) and the swing bracket ( 3 ), and the second pin shaft ( 802 ) is inserted into the limiting slide groove ( 801 ); and when the connecting plate ( 502 ) drives the crank ( 501 ) to rotate synchronously, the support plate seat ( 2 ) rises or falls, and the second pin shaft ( 802 ) and the limiting slide groove ( 801 ) slide relatively.   
     
     
         11 . The seat-backrest linkage device according to  claim 3 , further comprising a swing locking mechanism ( 9 ) configured to limit the swing bracket ( 3 ) in a horizontal state. 
     
     
         12 . The seat-backrest linkage device according to  claim 11 , wherein the side wings ( 3011 ) each comprise a horizontally arranged side wing body ( 30111 ) and a wing plate ( 30112 ) vertically bent from an edge of the side wing body ( 30111 ); the side lugs ( 1011 ) each comprise a side lug body ( 10111 ) and a lug plate ( 10112 ) vertically bent from an edge of the side lug body ( 10111 ); the swing locking mechanism ( 9 ) comprises a locking pin ( 901 ); the wing plate ( 30112 ) and the lug plate ( 10112 ) are partially staggered up and down, and a guide hole ( 30113 ) and a locking hole ( 10113 ) opposite to each other in a horizontal direction are formed in the up-down staggered part; the locking pin ( 901 ) is inserted in the guide hole ( 30113 ), and the locking pin ( 901 ) is controlled to move; when the locking pin ( 901 ) is synchronously inserted in the guide hole ( 30113 ) and the locking hole ( 10113 ), the swing bracket ( 3 ) is in a locked state; and when the locking pin ( 901 ) leaves the locking hole ( 10113 ) and is inserted only in the guide hole ( 30113 ), the swing bracket ( 3 ) is unlocked. 
     
     
         13 . The seat-backrest linkage device according to  claim 12 , wherein the lug plate ( 10112 ) comprises a support lug ( 10114 ) perpendicular to left and right side walls of the base, the support lug ( 10114 ) continuously extends upwards to form a convex lug ( 10115 ), the convex lug ( 10115 ) and the wing plate ( 30112 ) adjacent thereto are staggered up and down, the convex lug ( 10115 ) is located on an outer side of the wing plate ( 30112 ) adjacent thereto, the locking hole ( 10113 ) is formed in the convex lug ( 10115 ), and the guide hole ( 30113 ) is formed in the wing plate ( 30112 ). 
     
     
         14 . The seat-backrest linkage device according to  claim 12 , wherein the swing locking mechanism ( 9 ) comprises a locking pin control mechanism ( 902 ); the locking pin control mechanism ( 902 ) comprises a locking bracket ( 9021 ) fixed to a front wall of the swing bracket ( 3 ), and a wire control II ( 9022 ); the wire control II ( 9022 ) comprises an outer sleeve ( 90221 ), and a pull wire ( 90222 ) telescopically moving in the outer sleeve ( 90221 ); the outer sleeve ( 90221 ) is mounted on the locking bracket ( 9021 ); a part, exposed out of the outer sleeve ( 90221 ), of the pull wire ( 90222 ) is connected to a pull wire end ( 90223 ); a pressure spring ( 903 ) is further provided between the pull wire end ( 90223 ) and the locking bracket ( 9021 ); the pressure spring ( 903 ) is arranged along an extension direction of the pull wire ( 90222 ); torsion springs II ( 904 ) are symmetrically arranged on left and right sides of the pull wire end ( 90223 ); a collar in a middle of the torsion spring II ( 904 ) is sleeved on a fastening screw ( 905 ) connected to an upper portion of the swing bracket ( 3 ) such that the torsion spring II ( 904 ) rotates integrally around the fastening screw ( 905 ); the torsion springs II ( 904 ) are each provided with an elastic force arm I ( 9041 ) and an elastic force arm II ( 9042 ) that are respectively arranged on two sides of the fastening screw ( 905 ), a tail end of the elastic force arm I ( 9041 ) is rolled into a lantern ring ( 90411 ), the lantern ring ( 90411 ) passes through the pull wire ( 90222 ) to abut against the pull wire end ( 90223 ), and the elastic force arm II ( 9042 ) is bend and passes through a moving hole ( 3012 ) reserved in the wing plate ( 30112 ) to be connected to the locking pin ( 901 ); when the pull wire ( 90222 ) moves in a shortening direction, the pressure spring ( 903 ) is compressed to generate a reset elastic force while the pull wire end ( 90223 ) drives the elastic force arm I ( 9041 ) to rotate, and the locking pin ( 901 ) moves synchronously to enter or leave the locking hole ( 10113 ); and when the pull wire ( 90222 ) is released, that is, moving in a lengthening direction, the pressure spring ( 903 ) releases an elastic force to assist the pull wire end ( 90223 ), the torsion spring II ( 904 ), and the locking pin ( 901 ) in resetting. 
     
     
         15 . The seat-backrest linkage device according to  claim 8 , further comprising a lifting locking mechanism ( 7 ) configured to keep the support plate seat ( 2 ) raised or lowered to a horizontal state. 
     
     
         16 . The seat-backrest linkage device according to  claim 15 , wherein the lifting locking mechanism ( 7 ) comprises a locking plate ( 6 ); the locking plate ( 6 ) is located between a third pin shaft ( 308 ) and a second pin shaft ( 802 ), the locking plate ( 6 ) is movably connected to the second pin shaft ( 802 ), the locking plate ( 6 ) is fixedly connected to the third pin shaft ( 308 ), and a plurality of pin holes ( 601 ) are formed in a front end of the locking plate ( 6 ) exceeding the third pin shaft ( 308 ); the lifting locking mechanism ( 7 ) further comprises opposite side vertical plates ( 701 ); the side vertical plates ( 701 ) are fixed on a front wall of the swing bracket ( 3 ), the side vertical plates ( 701 ) are parallel to the locking plate ( 6 ), and guide holes ( 7011 ) are formed in the side vertical plates ( 701 ); the lifting locking mechanism ( 7 ) further comprises insertion pins ( 705 ); the insertion pins ( 705 ) are inserted in the guide holes ( 7011 ), and the insertion pins ( 705 ) are controlled to move; when the insertion pins ( 705 ) are synchronously inserted in the guide holes ( 7011 ) and the pin holes ( 601 ), the locking plate ( 6 ) is in a locked state; and when the insertion pins ( 705 ) leave the pin holes ( 601 ) and are inserted only in the guide holes ( 7011 ), the locking plate ( 6 ) is unlocked. 
     
     
         17 . The seat-backrest linkage device according to  claim 15 , wherein the lifting locking mechanism ( 7 ) further comprises an insertion pin control mechanism ( 702 ); the insertion pin control mechanism ( 702 ) comprises a wire control bracket ( 7021 ) fixed to a periphery of the side vertical plates ( 701 ), and a wire control I ( 7022 ); the wire control I ( 7022 ) comprises an outer tube ( 70221 ), and a pull rope ( 70222 ) telescopically moving in the outer tube ( 70221 ); the outer tube ( 70221 ) is mounted on the wire control bracket ( 7021 ); a part, exposed out of the outer tube, of the pull rope ( 70222 ) is connected to a pull rope end ( 70223 ); a waist-shaped pressure spring ( 7023 ) is further provided between the pull rope end ( 70223 ) and the wire control bracket ( 7021 ); the waist-shaped pressure spring ( 7023 ) is arranged along an extension direction of the pull rope ( 70222 ); a torsion spring I ( 7024 ) is provided on a right side of the pull rope end; a collar in a middle of the torsion spring I ( 7024 ) is sleeved on a fastening screw ( 7025 ) at an upper portion of the wire control bracket ( 7021 ) such that the torsion spring I ( 7024 ) rotates integrally around the fastening screw ( 7025 ); the torsion spring I ( 7024 ) is provided with an elastic arm I ( 70241 ) and an elastic arm II ( 70242 ) that are respectively arranged on two sides of the fastening screw ( 7025 ), a tail end of the elastic arm I ( 70241 ) is rolled into a lantern ring ( 702411 ), the lantern ring ( 702411 ) passes through the pull rope ( 70222 ) to abut against the pull rope end ( 70223 ), and the elastic arm II ( 70242 ) is bend and inserted in a right side of the insertion pin ( 705 ); when the pull rope ( 70222 ) moves in a shortening direction, the waist-shaped pressure spring ( 7023 ) is compressed to generate a reset elastic force while the pull rope end ( 70223 ) drives the elastic arm I ( 70241 ) to rotate, and the insertion pins ( 705 ) move synchronously to enter the pin holes ( 601 ); and when the pull rope ( 70222 ) is released, that is, moving in a lengthening direction, the waist-shaped pressure spring ( 7023 ) releases an elastic force to assist the pull rope end ( 70223 ), the torsion spring I ( 7024 ), and the insertion pins ( 705 ) in resetting. 
     
     
         18 . The seat-backrest linkage device according to  claim 16 , wherein limiting bosses ( 602 ) are provided at upper and lower parts of the front end of the locking plate ( 6 ) facing outwards, a fixing pin ( 603 ) is fixed to an upper end of the side vertical plate ( 701 ), an end of the fixing pin ( 603 ) facing the locking plate ( 6 ) protrudes from the side vertical plate ( 701 ) to form a limiting end ( 6031 ), and when the support plate seat ( 2 ) is hoisted or reset to a horizontal position, the fixing pin ( 603 ) is always located between the two bosses ( 602 ). 
     
     
         19 . The seat-backrest linkage device according to  claim 3 , wherein the side wing ( 3011 ) and the side lug ( 1011 ) are oppositely arranged up and down, the elastic mechanisms ( 4 ) each comprise elastic rubber ( 404 ), and when the side wing ( 3011 ) swings along with the swing bracket ( 3 ), the elastic rubber ( 404 ) is compressed to generate a reset elastic force. 
     
     
         20 . The seat-backrest linkage device according to  claim 19 , wherein mounting columns ( 4041 ) are provided at two ends of the elastic rubber ( 404 ), and the two mounting columns ( 4041 ) are fixedly inserted in preset holes in the side wing ( 3011 ) and the side lug ( 1011 ), respectively.