Mechanical Stretching Device for Movable Seat Unit and Seat Unit

Abstract

The present disclosure relates to a mechanical stretching device for movable seat unit, in which the mechanical stretching device includes: a seat support, arranged to attach to a seat; a leg stretching device, pivoted at a front part of the seat support; a backrest support, pivoted at a rear part of the seat support; and an electrically actuated unit, including a leg electrically actuated device for folding and unfolding of the leg stretching device and a backrest electrically actuated device for backward reclining or forward resetting of the backrest support. Furthermore, the present disclosure further relates to a movable seat unit.

1 . A mechanical stretching device for movable seat unit, comprising:
 a seat support, arranged to attach to a seat;   a leg stretching device, pivoted at a front part of the seat support;   a backrest support, pivoted at a rear part of the seat support; and   an electrically actuated unit, comprising a leg electrically actuated device for folding and unfolding of the leg stretching device and a backrest electrically actuated device for backward reclining or forward resetting of the backrest support, wherein the mechanical stretching device is directly switched at least between a sitting position and a lying position, the leg stretching device is folded below the seat support in the sitting position, the leg stretching device is lifted forwards and upwards and the backrest support is reclining backwards in the lying position, stretching of the leg stretching device and backward reclining of the backrest support are performed simultaneously through the electrically actuated unit when the mechanical stretching device is switched from the sitting position to the lying position, and unfolding of the leg stretching device and forward resetting of the backrest support are performed simultaneously when the mechanical stretching device is switched from the lying position to the sitting position.   
     
     
         2 . The mechanical stretching device according to  claim 1 , wherein the mechanical stretching device is directly switched between the sitting position and a relaxing position, when in the relaxing position, the leg stretching device is lifted forwards and upwards, and a relative position between the backrest support and the seat support is kept to be the same in the sitting position. 
     
     
         3 . The mechanical stretching device according to  claim 2 , wherein the mechanical stretching device is sequentially switched from the sitting position to the lying position and then to the relaxing position by means of the electrically actuated unit. 
     
     
         4 . The mechanical stretching device according to  claim 1 , wherein the leg electrically actuated device acts between the leg stretching device and the seat support, and the backrest electrically actuated device acts between the backrest support and the seat support. 
     
     
         5 . The mechanical stretching device according to  claim 4 , wherein a leg crossbar is rigidly connected to the leg stretching device, a seat crossbar is rigidly connected to the seat support, an end of the leg electrically actuated device is pivoted to the leg crossbar, an opposite end of the leg electrically actuated device is pivoted to the seat crossbar, and the leg electrically actuated device drives the leg crossbar to move away from or close to the seat crossbar, so that the leg stretching device is unfolded or folded. 
     
     
         6 . The mechanical stretching device according to  claim 5 , wherein a backrest crossbar is rigidly connected to the backrest support, an end of the backrest electrically actuated device is pivoted to the backrest crossbar, an opposite end of the backrest electrically actuated device is pivoted to the seat crossbar, the backrest electrically actuated device drives the backrest crossbar to move away from or close to the seat crossbar, so that the backrest support is reclined backwards or reset forwards. 
     
     
         7 . The mechanical stretching device according to  claim 1 , wherein at least one of the leg electrically actuated device and the backrest electrically actuated device is a linear electric actuator. 
     
     
         8 . The mechanical stretching device according to  claim 3 , further comprising a base assembly for supporting the mechanical stretching device on the ground, the seat support is connected to the base assembly by means of a link mechanism, so as to swing in a front-back direction of the seat unit with respect to the base assembly. 
     
     
         9 . The mechanical stretching device according to  claim 8 , wherein the link mechanism comprises a swing base plate, a front swing rod, a back swing rod and a transmission connecting rod, respective upper end of both the front swing rod and back swing rod is pivoted to the swing base plate, respective lower end of both the front swing rod and back swing rod is pivoted to the transmission connecting rod, the swing base plate is fixedly connected to the base assembly, and the transmission connecting rod is connected to the seat support. 
     
     
         10 . The mechanical stretching device according to  claim 8 , further comprising a swing limit mechanism, wherein the swing limit mechanism allows the seat support to swing with respect to the base assembly in the sitting position of the mechanical stretching device, and the swing limit mechanism prevents the seat support from swinging with respect to the base assembly in the relaxing position or the lying position of the mechanical stretching device. 
     
     
         11 . A movable seat unit, comprising a seat, a backrest, a footrest member, and a mechanical stretching device, wherein the mechanical stretching device comprises:
 a seat support, arranged to attach to the seat;   a leg stretching device, arranged to attach to the footrest member, pivoted to a front part of the seat support;   a backrest support, arranged to attach to the backrest, pivoted to a rear part of the seat support; and   an electrically actuated unit, comprising a leg electrically actuated device for folding and unfolding of the leg stretching device and a backrest electrically actuated device for backward reclining or forward resetting of the backrest support, wherein the seat unit is directly switched at least between a sitting position and a lying position, the leg stretching device is folded below the seat support in the sitting position, the footrest member is lifted forwards and upwards and the backrest is reclining backwards in the lying position, lifting up of the footrest member and backward reclining of the backrest are performed simultaneously through the electrically actuated unit when the seat unit is switched from the sitting position to the lying position, and recovery of the footrest member and forward resetting of the backrest are performed simultaneously by means of the electrically actuated unit when the seat unit is switched from the lying position to the sitting position.   
     
     
         12 . The seat unit according to  claim 11 , wherein the seat unit is directly switched between the sitting position and a relaxing position, when in the relaxing position, the footrest member is lifted forwards and upwards, and a relative position between the backrest and the seat is kept to be the same in the sitting position. 
     
     
         13 . The seat unit according to  claim 12 , wherein the seat unit is sequentially switched from the sitting position to the lying position and then to the relaxing position by means of the electrically actuated unit. 
     
     
         14 . The seat unit according to  claim 11 , wherein the leg electrically actuated device acts between the leg stretching device and the seat support, and the backrest electrically actuated device acts between the backrest support and the seat support. 
     
     
         15 . The seat unit according to  claim 14 , wherein a leg crossbar is rigidly connected to the leg stretching device, a seat crossbar is rigidly connected to the seat support, an end of the leg electrically actuated device is pivoted to the leg crossbar, an opposite end of the leg electrically actuated device is pivoted to the seat crossbar, and the leg electrically actuated device drives the leg crossbar to move away from or close to the seat crossbar, so that the leg stretching device is unfolded or folded. 
     
     
         16 . The seat unit according to  claim 15 , wherein a backrest crossbar is rigidly connected to the backrest support, an end of the backrest electrically actuated device is pivoted to the backrest crossbar, an opposite end of the backrest electrically actuated device is pivoted to the seat crossbar, the backrest electrically actuated device drives the backrest crossbar to move away from or close to the seat crossbar, so that the backrest support is reclined backwards or reset forwards. 
     
     
         17 . The seat unit according to  claim 11 , wherein at least one of the leg electrically actuated device and the backrest electrically actuated device is a linear electric actuator. 
     
     
         18 . The seat unit according to  claim 13 , wherein a base assembly for supporting the mechanical stretching device on the ground, the seat support is connected to the base assembly by means of a link mechanism, so as to swing in a front-back direction of the seat unit with respect to the base assembly. 
     
     
         19 . The seat unit according to  claim 18 , wherein the link mechanism comprises a swing base plate, a front swing rod, a back swing rod and a transmission connecting rod, respective upper end of both the front swing rod and back swing rod is pivoted to the swing base plate, respective lower end of both the front swing rod and back swing rod is pivoted to the transmission connecting rod, the swing base plate is fixedly connected to the base assembly, and the transmission connecting rod is connected to the seat support. 
     
     
         20 . The seat unit according to  claim 18 , wherein a swing limit mechanism, wherein the swing limit mechanism allows the seat support to swing with respect to the base assembly in the sitting position of the seat unit, and the swing limit mechanism prevents the seat support from swinging with respect to the base assembly in the relaxing position or the lying position of the seat unit.