Patent Publication Number: US-2022225781-A1

Title: Sofa bed

Description:
PRIORITY CLAIM 
     This application claims the benefit of Chinese Patent Application No. 202110064263.9, filed Jan. 18, 2021, which is incorporated herein by reference. 
     FIELD 
     The present disclosure relates to the design of furniture, and specifically to a sofa bed. 
     BACKGROUND 
     With incremental improvements of people&#39;s material well-being life, the need of the consumer for household furniture presents a trend of diversification, wherein sofa beds already become a type of popular furniture products. The conventional sofa beds have some drawbacks, such as for example, the switching of the conventional sofa beds between two states is not smooth enough, so that it is usually difficult for an operator with less power to complete the switching individually; the conventional sofa beds might not be stable enough in the sofa state, and an angle between the seat and the backrest might be changed, which affects the degree of comfort; and the folding manner of the conventional sofa beds is single and thus cannot satisfy the user&#39;s various demands. 
     Therefore, it is desirable to provide a sofa bed to at least partially solve the above problems. 
     SUMMARY 
     A main object of the present invention is to provide a sofa bed which is easily switchable between two in-use positions and easy to operate. Furthermore, in a predetermined switching procedure and a predetermine use procedure, an angle between a seat portion and a backrest portion can be locked to improve the reliability of the operation. In the switching operation, by allowing a pin to slide in a sliding groove in an extension direction having a transverse component and a vertical component, the burden of an user in operation can be lightened, and the switching operation can be achieved quickly and easily. Furthermore, the sofa bed may be provided with a plurality of detachable elastic modules which are simple to mount and convenient to operate. Thus, the user may manually mount them to obtain a sofa bed having a better degree of comfort. 
     According to an aspect of the present invention, there is provided a sofa bed, comprising: 
     a main body frame comprising a seat portion and a backrest portion arranged adjacent to each other, the seat portion and the backrest portion being configured to be folded or unfolded about a locking mechanism, so that the main body frame is changed between a bed configuration and a sofa configuration; and 
     an armrest frame respectively disposed on both sides of the main body frame in a longitudinal direction, and connected to the main body frame via the locking mechanism, wherein each of the armrest frames is formed with a slideway through which the movement of the locking mechanism is guided, 
     wherein, when the backrest portion and the seat portion are pivotal relative to each other about the locking mechanism, the sofa bed is configured to lock the backrest portion relative to the seat portion at a predetermined angle, and allow the locking mechanism to drive the main body frame to displace while the locking mechanism being guided by the slideway in a locked state. 
     According to a preferable embodiment of the present invention, the locking mechanism comprises: 
     a seat portion connecting rod attached to and extending along a transverse side edge of the seat portion; 
     a backrest portion connecting rod attached to a transverse side edge of the backrest portion on the same side as the transverse side edge of the seat portion and extending along the transverse side edge of the backrest portion; and 
     a pivot shaft connecting the seat portion connecting rod with the backrest portion connecting rod so that the backrest portion and the seat portion can pivot relative to each other. 
     According to another preferable embodiment of the present invention, the main body frame is configured to release the locking between the seat portion connecting rod and the backrest portion connecting rod when the seat portion arranged in the locked stated is operated to pivot towards the backrest portion. 
     According to a further preferable embodiment of the present invention, one of the seat portion connecting rod and the backrest portion connecting rod is provided with a ratchet, and the other of the seat portion connecting rod and the backrest portion connecting rod is provided with a pawl, wherein the ratchet and the pawl engage with each other so that the backrest portion is locked at a predetermined angle with respect to the seat portion. 
     According to a further preferable embodiment of the present invention, an outer edge of the ratchet is provided with a recessed portion that is recessed inward in a radial direction of the ratchet, and the pawl is provided with a protruding portion corresponding to the recessed portion, wherein the protruding portion is configured to enable the protruding portion to engage the recessed portion when the backrest portion and the seat portion form the predetermined angle, thereby locking the backrest portion and the seat portion. 
     According to a further preferable embodiment of the present invention, both the seat portion and the backrest portion are formed as a rectangular structure. 
     According to a further preferable embodiment of the present invention, a side edge of the seat portion extending in the longitudinal direction and a side edge of the backrest portion extending in the longitudinal direction are arranged adjacent to each other. 
     According to a further preferable embodiment of the present invention, the main body frame is configured such that the backrest portion can be locked at a plurality of different predetermined angles relative to the seat portion. 
     According to a further preferable embodiment of the present invention, the main body frame further comprises a driven beam, one end of the driven beam is pivotally connected to the armrest frame, and the other end of the driven beam is pivotally connected to the backrest portion. 
     According to a further preferable embodiment of the present invention, the armrest frame comprises a substantially  -shaped armrest frame body (referred to as a “channel shape”) and a reinforcing transverse beam connected between two legs of the armrest frame body, and the slideway is formed on the reinforcing transverse beam. 
     According to a further preferable embodiment of the present invention, the locking mechanism is provided with a pin extending toward the outside of the main body frame, and the slideway is a sliding groove formed on the reinforcing transverse beam, one end of the slideway is positioned higher than the other end of the slideway, and the one end is open toward an upper edge of the armrest frame so as to receive the pin of the locking mechanism. 
     According to another preferable embodiment of the present invention, the reinforcing transverse beam is provided with a sliding rod, and the locking mechanism is provided with a sliding sleeve which is configured to be sleeved on the sliding rod and slide along the sliding rod. 
     According to a further preferable embodiment of the present invention, a sliding rod is provided under the reinforcing transverse beam, and the sliding rod and a lower edge of the reinforcing transverse beam jointly define the sliding groove. 
     According to a further preferable embodiment of the present invention, a cross section of the reinforcing transverse beam is in a shape of  , and an outer end of the pin is provided with a protrusion that can mating with the   shape. 
     According to a further preferable embodiment of the present invention, the sofa bed comprises a bottom supporting structure that is disposed under the backrest portion and the seat portion and is fixedly connected to the two armrest frames. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Reference may be made to preferred embodiments shown in the figures to enable better understanding of the above and other objects, features, advantages and functions of the present invention. The same or like reference numerals in the figures denote the same or like parts. Those skilled in the art should appreciate that the figures are intended to schematically illustrate the preferred embodiments of the present invention, and not intended to limit the scope of the present invention, and all parts shown in the figures are not drawn to scale. 
         FIG. 1  is a perspective schematic view of a main body frame of a sofa bed according to a preferred embodiment of the present invention when it is arranged in a bed state; 
         FIG. 2  is a side view of the sofa bed shown in  FIG. 1 ; 
         FIG. 3  is a perspective schematic view of the main body frame of  FIG. 1  in a sofa state; 
         FIG. 4  is a side view of the sofa bed shown in  FIG. 3 ; 
         FIG. 5  is an exploded schematic view of a junction of a seat portion and a backrest portion in the present embodiment; 
         FIG. 6A - FIG. 6F  are side views of the main body frame according to the preferred embodiment, which sequentially show a process in which the sofa transitions from a first in-use state to a second in-use state, and then return back to the first in-use state; 
         FIG. 7A  shows a schematic diagram of a sliding groove in the preferred embodiment; 
         FIG. 7B - FIG. 7D  are alternative implementations of the sliding groove shown in  FIG. 7A ; 
         FIG. 7E  is a cross-sectional view taken along line C-C indicated in  FIG. 7D , wherein hatching lines are omitted in  FIG. 7E  for a clearer illustration purpose: 
         FIG. 8  is a schematic diagram of an elastic module of a sofa bed according to a preferred embodiment of the present invention; 
         FIG. 9 - FIG. 11  are schematic diagrams of a process in which an elastic module is mounted to the main body frame; 
         FIG. 12  is a schematic diagram after elastic modules are mounted on the main body frame; 
         FIG. 13  and  FIG. 14  are respective schematic diagrams showing shapes of a finished product of the sofa bed. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Specific embodiments of the present prevention will now be described in detail with reference to the figures. What are described here are only preferred embodiments according to the present invention. Those skilled in the art can implement other embodiments of the present invention on the basis of the preferred embodiments, and said other embodiments also fall within the scope of the present invention. 
     The invention provides a sofa bed.  FIG. 1 - FIG. 7E  show at least partial structures according to some preferred embodiments of the present invention. First, it will be appreciated that “transverse direction” and “longitudinal direction” mentioned in the present invention refer to absolute directions, and respectively two directions perpendicular to each other in a horizontal plane, wherein the transverse direction is shown by X in the figures, and the longitudinal direction is shown by Y in the figures; “widthwise direction” and “lengthwise direction” mentioned in the present invention refer to relative directions relative to a rectangle formed by a seat portion and a backrest portion, but the lengthwise direction always coincides with the longitudinal direction Y, the widthwise direction coincides with the transverse direction X only when the seat portion and/or backrest portion are placed horizontally. A height direction mentioned in the context is an absolute vertical direction and shown by Z in the figures. 
       FIG. 1 - FIG. 14  show some preferred embodiments of the present invention. 
     Referring to  FIG. 1  through  FIG. 4 , a sofa bed according to a preferred embodiment of the present application comprising a main body frame  100  which includes a seat portion  4 , a backrest portion  3 , a seat portion connecting rod  41 , a backrest portion connecting rod  31 , and two armrest frames  2 . The seat portion  4  and the backrest portion  3  are both formed as a rectangular structure, which may be a rectangular frame structure or a rectangular plate-like structure. A longitudinal edge of the seat portion  4  and a longitudinal edge of the backrest portion  3  are butted together. 
     The seat portion connecting rod  41  is fixed on a widthwise edge of the seat portion  4 , the backrest portion connecting rod  31  is fixed on a widthwise edge of the backrest portion  3 , and the seat portion connecting rod  41  and the backrest connecting rod  31  are connected together in a way that they are pivotable relative to each other. When the seat portion connecting rod  41  and the backrest portion connecting rod  31  pivot relative to each other, an angle formed therebetween increases or decreases. It will be appreciated that the “angle” mentioned in the present invention refers to an angle less than or equal to 180°. 
     The two armrest frames  2  are provided at both ends of the seat portion  4  and the backrest portion  3  in the longitudinal direction, and each of the armrest frames  2  is provided with a slideway that opens toward the backrest portion  3  and the seat portion  4  and partially extends in the transverse direction. In the present embodiment, the slideway is a sliding groove  211 , and a rear end  211   b  of the sliding groove  211  is positioned lower than a front end  211   a  of the sliding groove  211 . 
     The exploded schematic view of the pivotal connection of the seat portion  4  and the backrest portion  3  is shown in  FIG. 5 . Referring to  FIG. 5 , the seat portion connecting rod  41  and the backrest portion connecting rod  31  are engaged with each other at a locking mechanism  34 , and the locking mechanism  34  has a pin  341  protruding from a side facing the armrest. The front end  211   a  of the sliding groove  211  is provided with an upward opening, so that the pin  341  can enter into the sliding groove  211  from the front end  211   a  of the sliding groove  211  and slide in the sliding groove  211 . A special-shaped gear and a gear matching claw are provided at the locking mechanism  34 , and they are respectively disposed on the seat portion connecting rod  41  and the backrest portion connecting rod  31 . The special-shaped gear is for example a ratchet wheel  342 , wherein the edge of the ratchet  342  is provided with a recessed portion that is recessed in a radial direction of the ratchet  342 . The gear matching pawl is provided with a protruding portion that mates with the recessed portion. The recessed portion and the protruding portion are positioned such that when the backrest portion  3  and the seat portion  4  are located at a predetermined obtuse angle, the protruding portion is embedded or inserted in the recessed portion to achieve locking. The seat portion  4  is provided with a seat portion insertion sleeve  42  for accommodating the seat portion connecting rod  41 , and the backrest portion  3  is provided with a backrest portion insertion sleeve  32  for accommodating the backrest portion connecting rod  31 . 
     Furthermore, each armrest frame  2  includes an armrest frame body  22  and a reinforcing transverse beam  21 , wherein the sliding groove  211  is disposed on the reinforcing transverse beam  21 , and an extension direction of the reinforcing transverse beam  21  coincides with that of the sliding groove  21 , i.e., the rear end  211   b  of the reinforcing transverse beam  21  is also positioned lower than the front end  211   a  of the reinforcing transverse beam  21 . The armrest frame body  22  further includes two upright columns extending in the vertical direction and a body transverse beam connected at the tops of the two upright columns. The reinforcing transverse beam is connected to the middle of the two upright columns and is parallel to the body transverse beam. 
     In addition to the armrest frame  2 , the supporting and fixing structure of the sofa bed further includes a bottom supporting structure  24  which is disposed under the backrest portion  3  and the seat portion  4  and is fixedly connected to the two armrest frames  2 . The bottom supporting structure  24  includes for example a bottom supporting structure longitudinal beam, a bottom supporting structure transverse beam  23  and legs  25 . The sofa bed further includes a driven beam  26 , one end of which is pivotally connected to the armrest frame  2 , and the other end of which is pivotally connected to the backrest portion  3 . 
       FIG. 6A - FIG. 6F  show a process in which the main body frame  100  changes from a first in-use position (at which the sofa bed is used as a bed) to a second in-use position (at which the sofa bed is used as a sofa) and then returns back to the first in-used position. 
     First, referring to  FIG. 6A , when the main body frame  100  is located at the first in-use position, the backrest portion  3  and the seat portion  4  are both horizontal, and the angle formed therebetween is a straight angle. The angle formed between the backrest portion connecting rod  31  and the seat portion connecting rod  41  is also substantially a straight angle, and the pivot axis of the locking mechanism  34  is substantially located adjacent to the front end  211   a  of the sliding groove  211 . At this time, the backrest portion connecting rod  31  and the seat portion connecting rod  41  are not locked, thereby allowing the seat portion  4  to be operated to pivot toward a position where the angle between the seat portion  4  and the backrest portion  3  is reduced. The direction of the pivoting is shown by an arrow in  FIG. 6A . 
     When it requires to adjust the main body frame  100  to the second in-use position, the seat portion  4  can be pivoted in the direction shown by the arrow in  FIG. 6A , to a position shown in  FIG. 6B . At the position shown in  FIG. 6B , the pivoting between the backrest portion connecting rod  31  and the seat portion connecting rod  41  is locked. Specifically, for example, the locking mechanism  34  may be provided with a special-shaped ratchet  342  and a special-shaped pawl which have shapes matching to each other. The special-shaped ratchet  342  and the special-shaped pawl are shaped to snap fit together at the position shown in  FIG. 6B  to prevent the seat portion  4  from further rotating relative to the backrest portion  3 . At this time, the angle between the seat portion  4  and the backrest portion  3  is a, which is an obtuse angle. The “predetermined obtuse angle” mentioned in the present invention may be understood as a shown in  FIG. 6B . 
     At this time, the pin  341  at the locking mechanism  34  can enter into the sliding groove  211  from the front end  211   a  of the sliding groove  211 . Then, as shown in  FIG. 6C , the seat portion  4  may be pressed down along an arc-shaped arrow, and meanwhile the pin  341  can drive the combination of the backrest portion  3  and the seat portion  4  to slide in a direction indicated by a straight arrow in  FIG. 6C . After this operation, the combination of the backrest portion  3  and the seat portion  4  can reach the second in-use position as shown in  FIG. 6D . 
     In the structure shown in  FIG. 6B  through  FIG. 6D , the backrest portion connecting rod  31  and the seat portion connecting rod  41  are locked to each other at the locking mechanism  34 , and the angle between the backrest portion  3  and the seat portion  4  is always α. 
     When it is required to change the main body frame  100  from the second in-use position to the first in-use position, the seat portion  4  can be manually operated to further pivot toward the backrest portion  3  in the direction indicated by the arrow as shown in  FIG. 6D . The action for example can make the protruding portion of the pawl disengage from the recessed portion of the ratchet, thereby releasing the locking between the seat portion connecting rod  41  and the backrest portion connecting rod  31 . 
     Referring to  FIG. 6E , after the seat portion  4  is pivoted in the direction indicated by arrow A, the locking between the seat portion connecting rod  41  and the backrest portion connecting rod  31  is released. After the unlocking, the pin  341  is slided in the sliding groove  211  toward the front end  211   a  in the direction indicated by the arrow B, thereby driving the backrest portion  3  and the seat portion  4  to reach the position shown in  FIG. 6F , so that the main body frame  100  returns to the first in-use position. 
       FIG. 7A  shows details of the sliding groove  211  in  FIG. 1  through  FIG. 6F . In the  FIG. 7A , the sliding groove  211  is a groove structure formed on the reinforcing transverse beam  21  itself of the armrest frame  2 .  FIG. 7B  through  FIG. 7D  show some alternative embodiments of  FIG. 7A . 
     In the embodiment shown in  FIG. 7B , the reinforcing transverse beam  21   a  is provided with a sliding rod  212 , and a sliding sleeve  341   a  is fixedly fixed at the locking mechanism of the backrest portion connecting rod and the seat portion connecting rod to engage with and slide on the sliding rod  212 . 
     In the embodiment shown in  FIG. 7C , a sliding rod is disposed under the reinforcing transverse beam  21   b , the sliding rod and the lower edge of the reinforcing transverse beam  21   b  jointly define a sliding groove  213 , and a pin  341   b  fixedly disposed at the locking mechanism of the backrest portion connecting rod and the seat portion connecting rod can engage with and slide in the sliding groove  213 . 
     In the embodiment shown in  FIG. 7D , the reinforcing transverse beam  21   c  is a special-shaped beam whose cross section is shown in  FIG. 7E . Referring to  FIG. 7E , the cross-section of the reinforcing transverse beam  21   c  is in a shape of  , and a pin  341   c  is fixedly disposed at the locking mechanism of the backrest portion connecting rod and the seat portion connecting rod, wherein a projection having a shape that can mate with the   shape is provided  at an outer end of the pin  341   c , and the projection can be adaptively received in the  1 L shaped beam so that the pin  341   c  can slide along the sliding groove  214  without disengaging from the sliding groove  214 . Two stoppers ae provided in the  -shaped beam, wherein a front stopper  214   b  can constitute the front end of the sliding groove  214 , and a rear stopper  214   a  can constitute the rear end of the sliding groove  214 . 
     In addition to the above structure, the sofa bed according to the present invention may further include a plurality of elastic modules.  FIG. 8  shows an example of an elastic module. Referring to  FIG. 8 , each of the elastic modules  200  includes a conical spring  110  and a spring bracket  121  accommodating the conical spring. The spring bracket  121  includes a base, an end cover  122  and one or more sets of flexible straps  123 . The base includes a base of a spring mounting seat, and each spring mounting seat has a spring fixing portion for fixing one end of the conical spring  110 . The end cover  122  is arranged opposite to and cooperative with the corresponding spring mounting seat to hold the conical spring  110 , wherein the end cover  122  abuts against the other end of the conical spring  100  opposite to the end fixed in the spring mounting seat. Each set of flexible straps  123  includes a plurality of flexible straps spaced apart and evenly arranged between a corresponding pair of spring mounting seat and end cap. When one conical spring  110  is retained between the corresponding pair of spring mounting seat and end cap  122 , the flexible straps  123  are located outside the conical spring  110 . Alternatively, the sofa bed further includes a cover covering the conical springs. 
     Referring to  FIG. 9  through  FIG. 11 , the main body frame is provided with slide rails (including a transverse slide rail  400  and longitudinal slide rails  300 ) which are configured in a way that a plurality of elastic modules  200  can be mounted on the main body frame from the outside of the main body frame and slide to a predetermined mounting position, so that a plurality of elastic modules  200  are closely arranged on a side of the main body frame facing the user (as shown in  FIG. 12 ). 
     Preferably, the conical spring is mounted in the spring bracket with a predetermined initial compression force. 
     For example, referring to  FIG. 9 , the plurality of slide rails includes longitudinal slide rails  300 , the longitudinal ends  301  of which are open, so that the elastic modules  200  can be received. Alternatively, the plurality of slide rails includes transverse side rails  400  whose transverse ends  401  are open so that the elastic modules  200  can be received. 
     Referring to  FIG. 10  and  FIG. 11 , the plurality of slide rails include a plurality of longitudinal slide rails  300  extending in the longitudinal direction and a transverse slide rail  400  extending in the transverse direction. The longitudinal slide rails and transverse slide rails communicate at their intersections to facilitate the elastic modules  200  to switch side rails. Specifically, the transverse slide rail  400  is disposed in the middle of the longitudinal direction Y of the main body frame, and the transverse end  401  of the transverse slide rail  400  is opened to receive the elastic module  200  from the outside of the main body frame. The arrangement of the plurality of slide rails are designed such that the plurality of elastic modules  200  can enter the transverse slide rail  400  on the main body frame from the end of the main body frame, and switch to the longitudinal slide rails  300  at the intersection of the transverse slide rails  400  and the longitudinal slide rail  300 . 
     In a state that a plurality of elastic modules  200  are closely arranged on the side of the main body frame facing the user as shown in  FIG. 12 , an outer covering may be further provided on the elastic modules to obtain a sofa bed finished product as shown in  FIG. 13  and  FIG. 14 .  FIG. 13  shows a configuration of the sofa bed finished product as a bed;  FIG. 14  shows a configuration of the sofa bed finished product as a sofa. 
     The above depictions of various embodiments of the present invention are provided to those having ordinary skill in the art for depiction purpose, and are not intended to exclude other embodiments from the present prevention or limit the present prevention to a single disclosed embodiment. As described above, various alternatives and modifications of the present prevention will be apparent to those of ordinary skill in the art. Accordingly, although some alternative embodiments have been described in detail, those having ordinary skill in the art will understand or readily develop other embodiments. The prevention is intended to cover all alternatives, modifications and variations of the present prevention described herein, as well as other embodiments falling within the spirit and scope of the present prevention described herein.