LINKAGE MECHANISM AND A FOLDING SOFA BED THAT INCLUDES SAME

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present Application for Patent claims priority to and the benefit of Chinese Patent Application No. 2025100249559 filed in the Chinese Patent Office on January 3, 2025, and hereby expressly incorporated by reference herein as if fully set forth below in its entirety and for all applicable purposes.

TECHNICAL FIELD

[0002] The present invention relates to the technical field of sofa furniture manufacturing, specifically to a linkage mechanism and a novel folding sofa bed that includes the linkage mechanism.

INTRODUCTION

[0003] Sofa beds are a type of furniture that can function both as a sofa for sitting and leaning, and as a bed through transformation, allowing people to lie down and rest. This dual-purpose design makes sofa beds highly versatile. In modern minimalist home layouts, sofa beds are a popular choice. They are often used in small apartments to accommodate occasional guests, making a sofa bed an essential piece of furniture. In small spaces, a sofa bed can be placed in the living room or study to serve as seating and can be unfolded into a bed when guests visit.

[0004] Sofa bed designs are varied, including foldable, pull-out, and flip-over types, which save space and serve multiple purposes. The market offers a wide range of sofa beds that not only meet consumer preferences but also address the cost-reduction needs of manufacturers. However, some sofa beds currently available have folding mechanisms that cannot effectively produce a soft backrest and require the use of detachable cushions. To unfold the sofa bed, users need to remove the cushions before folding the sofa bed into a bed, making the operation cumbersome. Additionally, these designs often have a deep seating area and a backrest that is too upright, which do not conform to ergonomic standards. Therefore, designing and manufacturing linkage mechanisms specifically for sofa beds is crucial.

[0005] For example, as disclosed in a Chinese patent application number CN202411258234.6, a horizontal two-fold sofa bed is achieved through the following technical solution: It includes a fixed base frame, a first linkage assembly, a left frame, a connecting component, a right frame, and a supporting component. The fixed base frame is equipped with a limiting component. One end of the first linkage assembly is pivotally connected to the fixed base frame. The first linkage assembly has a contact surface corresponding to the limiting component. The left frame is pivotally connected to the other end of the first linkage assembly. When the left frame unfolds over the fixed base frame, the contact surface of the first linkage assembly abuts against the limiting component to prevent the first linkage assembly from rotating. One end of the connecting component is pivotally connected to one side of the left frame. One side of the right frame is pivotally connected to the other end of the connecting component. The right frame can be stored above the left frame via the connecting component or unfolded on one side of the left frame. The supporting component is pivotally connected below the right frame. In this application, the bed frame unfolds laterally, allowing users to lie horizontally and maximizing the use of floor space. However, this application can only achieve a two-fold mechanism and cannot flatten the headrest section of the sofa bed. Additionally, the sofa cushion is directly placed on the folded metal frame, making it impossible to integrate it with the frame, and the operation is relatively cumbersome.

[0006] Another example, disclosed in Chinese patent application number CN202411247188.X, achieves a technical solution for a three-section sofa bed. This sofa bed includes a rear frame, a middle frame, and a front frame. The rear frame has a first sliding rail on opposite sides. Both ends of the first sliding rail are equipped with a first inclined slope piece and a second inclined slope piece that connect the two ends. The middle frame has a second sliding rail on opposite sides, aligned with the first sliding rail. Both ends of the second sliding rail are equipped with a third inclined slope piece and a fourth inclined slope piece. One side of the middle frame near the third inclined slope piece is equipped with a first guide roller positioned on the first inclined slope piece. The front frame is positioned on the middle frame, and one side of the front frame near the third inclined slope piece is equipped with a second guide roller positioned on the third inclined slope piece. Although this application enables easy unfolding and folding of the three-section sofa bed, the structure does not integrate the rear frame when converting it back into a sofa. The backrest requires additional components, making the structure more complex.

[0007] Chinese patent application number CN202411186185.X discloses a technical solution for a linkage mechanism applied to a three-section sofa bed. It includes a first linkage assembly, a second linkage assembly, a third linkage assembly, and a locking assembly. One side of the first linkage assembly is pivotally connected to the front sofa cushion, while the other side is pivotally connected to the fixed base frame of the sofa. The first linkage assembly has a locking hole. One end of the second linkage assembly is pivotally connected to the middle sofa cushion, and the other end is pivotally connected to the middle of the first linkage assembly. One side of the third linkage assembly is pivotally connected to the rear sofa cushion, while the other side is pivotally connected to the pivot point of the first linkage assembly and the fixed base frame. The locking assembly is positioned on the side of the first linkage assembly near the front sofa cushion. The locking assembly includes a locking rod that corresponds to the locking hole. When the front sofa cushion unfolds via the first linkage assembly, it extends to the side of the middle sofa cushion. The locking assembly prevents further movement of the first linkage assembly by inserting the locking rod into the locking hole. While this application improves product safety, the linkage mechanism's structure is not the most streamlined, and additional components are needed for the sofa backrest, resulting in higher manufacturing costs. There is still room for further optimization.

BRIEF SUMMARY OF SOME EXAMPLES

[0008] The following presents a summary of one or more aspects of the present disclosure, in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated features of the disclosure, and is intended neither to identify key or critical elements of all aspects of the disclosure nor to delineate the scope of any or all aspects of the disclosure. Its sole purpose is to present some concepts of one or more aspects of the disclosure in a form as a prelude to the more detailed description that is presented later.

[0009] Aspects of the disclosure offer the following beneficial effects:

[0010] Innovative and Simple Structure: The linkage device features a simple and innovative design, concealed within the sides of the sofa bed. During folding operations, the structure remains stable and robust, with easy operation. The sliding rail component is a standout innovation; during operation, the sliding rail wheel moves back and forth within the sliding rail’s designated track, enabling smooth operation of the linkage device.

[0011] Integrated Cushion Design: The sofa bed’s outer frame, middle frame, and front frame can be directly upholstered with cushions. When folded, the outer and inner cushions of the sofa bed can work in tandem as the backrest of the sofa. The front cushion at the end of the sofa bed can flip upward to serve as the sofa seat cushion. When the sofa bed is folded back into the sofa form, the bed's end lifts upward, and the middle frame's springs and sliding rail retract to fold the headboard’s outer cushion and the middle inner cushion. This achieves a multifunctional transformation from the sofa’s sitting function to the sofa bed’s lying function.

[0012] Integrated Frame and Cushion Structure: Unlike the market’s common separate cushion and frame designs, where the cushions must be removed to fold the bed mechanism, this invention integrates the internal frame and cushions. This integration eliminates cumbersome usage, oversized seating depth, and overly upright backrests that do not meet ergonomic sitting comfort standards. The integrated structure allows effortless transformation between sofa and sofa bed, saving time and effort. Both the sitting and sleeping configurations are comfortable, meeting ergonomic requirements.

[0013] These and other aspects of the invention will become more fully understood upon a review of the detailed description, which follows. Other aspects, features, and implementations will become apparent to those of ordinary skill in the art, upon reviewing the following description of specific, exemplary implementations in conjunction with the accompanying figures. While features may be discussed relative to certain implementations and figures below, all implementations can include one or more of the advantageous features discussed herein. In other words, while one or more implementations may be discussed as having certain advantageous features, one or more of such features may also be used in accordance with the various implementations discussed herein. In similar fashion, while exemplary implementations may be discussed below as devices, systems, or methods, it should be understood that such exemplary implementations can be implemented in various devices, systems, and methods.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Aspects of the present disclosure are further explained below in conjunction with the accompanying drawings and examples:

[0015]FIG. 1 is a front and rear structural diagram of a linkage mechanism according to some aspects of the present disclosure.

[0016]FIG. 2 is a structural diagram of the linkage mechanism installed on a side wooden panel according to some aspects of the present disclosure.

[0017]FIG. 3 is a right-side view of the linkage mechanism installed within an internal structure of a sofa bed according to some aspects of the present disclosure.

[0018]FIG. 4 is a left-side view of the linkage mechanism installed within the internal structure of the sofa bed according to some aspects of the present disclosure.

[0019]FIG. 5 is a partial enlarged view of a spring component in the linkage mechanism according to some aspects of the present disclosure.

[0020]FIG. 6 is a partial enlarged view of a sliding rail and sliding wheels in the linkage mechanism according to some aspects of the present disclosure.

[0021]FIG. 7 is an internal structural diagram of a folding sofa bed containing the linkage mechanism after folded into a sofa according to some aspects of the present disclosure.

[0022]FIG. 8 is an internal structural diagram of the folding sofa bed containing the linkage mechanism after extended into a sofa bed according to some aspects of the present disclosure.

[0023]FIG. 9 is an internal structural diagram of the folding sofa bed containing the linkage mechanism after the sofa bed is extended according to some aspects of the present disclosure.

[0024]FIG. 10 is a partial enlarged view of a foot nail section of the folding sofa bed containing the linkage mechanism according to some aspects of the present disclosure.

[0025]FIG. 11 is a partial enlarged view of a bottom zipper section of the folding sofa bed containing the linkage mechanism according to some aspects of the present disclosure.

[0026]FIG. 12 is a perspective diagram of the folding sofa bed containing the linkage mechanism after it is folded into a sofa according to some aspects of the present disclosure.

[0027]FIG. 13 is another perspective diagram of the folding sofa bed containing the linkage mechanism after it is folded into a sofa according to some aspects of the present disclosure.

[0028]FIG. 14 is a perspective diagram of the folding sofa bed containing the linkage mechanism after it is extended into a sofa bed according to some aspects of the present disclosure.

Reference numerals in the figures:

[0029] 1 - Front frame fixing component, 2 - First linkage component, 3 - Second linkage component, 4 - Third linkage component, 5 - Fourth linkage component, 6 - Sliding rail component, 7 - Outer frame connecting component, 8 - Wooden frame fixing component, 9 - Position-limiting locking component, 10 - Spring, 11 - Front frame, 12 - Middle frame, 13 - Outer frame, 14 - Front wooden panel, 15 - Side wooden panel, 16 - Rear wooden panel, 17 - Fixed wooden frame, 18 - Foot nail, 21 - Front cushion, 22 - Inner cushion, 23 - Outer cushion, 24 - Armrest cushion, 25 - Covering cushion, 11-1 - Four side frames, 11-2 - Horizontal fixing component, 11-3 - Vertical fixing component, 13-1 - Bolt, 18-1 - L-shaped locking component, 23-1 - Zipper, 201 - Synchronous support rod, 601 - Sliding rail locking component, 602 - Sliding wheel.

DETAILED DESCRIPTION

[0030] The detailed description set forth below in connection with the appended drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well known structures and components are shown in block diagram form in order to avoid obscuring such concepts.

[0031] The present disclosure provides a linkage mechanism and a folding sofa bed that includes the linkage mechanism. The linkage mechanism features a novel and streamlined design, is hidden within the two sides of the sofa bed, and ensures structural stability during folding operations. Additionally, the outer frame, middle frame, and front frame of the sofa bed can be directly upholstered with cushions. The sofa bed is convenient to use and effectively resolves the problems in the prior art.

[0032]As shown in FIGS. 1-6, a linkage device includes a front frame fixing component (1), a first linkage component (2), a second linkage component (3), a third linkage component (4), a fourth linkage component (5), a sliding rail component (6), an outer frame connecting component (7), and a wooden frame fixing component (8). The middle part of the front frame fixing component (1) is fixed to the upper portion of the first linkage component (2), while its rear end is fixed to the upper portion of the second linkage component (3). The front frame fixing component (1) has a bent L shape. The first linkage component (2) has an F shape, with its middle section fixed to a sliding rail locking component (601) on the sliding rail component (6). The rear end of the first linkage component (2) is fixed to the lower portion of the second linkage component (3). The front end of the first linkage component (2) includes a limiting locking component (9) for securing the front frame fixing component (1) in place after it is extended.

[0033]The second linkage component (3) has an arc shape, with its middle section fixed to the sliding rail locking component (601). Its lower-middle section is fixed to the front end of the third linkage component (4), and its bottom end is fixed to the upper-middle portion of the fourth linkage component (5). The rear end of the third linkage component (4) is fixed to the outer frame connecting component (7), while the rear end of the fourth linkage component (5) is fixed to the wooden frame fixing component (8). The wooden frame fixing component (8) includes a limiting locking component (601), which is used to secure the outer frame connecting component (7) in position. A spring (10) is fixed between the lower-middle section of the second linkage component (3) and the lower-middle section of the fourth linkage component (5). The sliding rail component (6) has a grooved rail, allowing the sliding wheels (602) within it to roll back and forth, facilitating the movement of the middle frame (12).

[0034]The inside bottom of the first linkage component (2) is fixed with a synchronous support rod (201), which secures the linkage devices on both sides, enhancing the stability of the sofa bed. Together, the front frame fixing component (1), the first linkage component (2), the second linkage component (3), the third linkage component (4), the fourth linkage component (5), the sliding rail component (6), the outer frame connecting component (7), and the wooden frame fixing component (8) form a complete linkage device.

[0035]As shown in FIGS. 1-9, the front, middle, and rear ends of a linkage device are respectively fixed with a front frame (11), a middle frame (12), and an outer frame (13). The front frame (11) consists of four borders (11-1) with several horizontal fixing components (11-2) and vertical fixing components (11-3) secured inside the four borders (11-1). The front end of the front frame (11) is fixed to the front wooden plate (14), and its middle and rear ends are fixed to the front frame fixing component (1). The front and side ends of the middle frame (12) are fixed to the inner side of the sliding rail component (6) using sliding rail locking components (601), while the rear end is fixed to the front end of the outer frame (13) using bolts (13-1). The rear ends of the outer frame (13) are fixed to the wooden frame fixing component (8), which is secured to the side wooden plate (15). The side wooden plate (15) is fixed to the rear wooden plate (16), and its front end is equipped with a stabilizing wooden frame (17) to secure both side wooden plates (15). The bottom left and right sides of the front wooden plate (14) are fitted with foot nails (18), which are locked in place using L-shaped locking components (18-1).

[0036]As shown in FIGS. 11-14, a novel foldable sofa bed includes the aforementioned linkage device, a front cushion (21), an inner cushion (22), an outer cushion (23), armrest cushions (24), and a cover cushion (25). The front cushion (21) is fixed to the outside of the front frame (11) and serves as the sofa bed's seat cushion. The inner cushion (22) is fixed to the outside of the middle frame (12) and functions as the inner backrest cushion for the sofa bed. The outer cushion (23) is fixed to the outside of the outer frame (13) and serves as the sofa bed's outer cushion. The armrest cushions (24) are fixed to the outer sides of the side wooden plate (15) and are used as armrests when the sofa bed is folded into a sofa. The cover cushion (25) is fixed to the outside of the front wooden plate (14) and is used to cover the front part of the sofa bed. The lower part of the outer cushion (23) is sewn with a zipper (23-1) for easy removal and installation.

[0037] A linkage mechanism, including a front frame fixing component, a first linkage component, a second linkage component, a third linkage component, a fourth linkage component, a sliding rail component, an outer frame connecting component, and a wooden frame fixing component. The middle portion of the front frame fixing component is fixed to the upper portion of the first linkage component, and the rear end is fixed to the upper portion of the second linkage component. The front frame fixing component is bent into an L-shape. The first linkage component is F-shaped, with its middle portion fixed to a sliding rail locking component on the sliding rail component, and its rear end fixed to the lower portion of the second linkage component. A position-limiting locking component is provided at the front end of the first linkage component, which is used to lock and fix the front frame fixing component after it is extended. The second linkage component is arc-shaped, with its middle portion fixed to the sliding rail locking component, its lower-middle end fixed to the front end of the third linkage component, and its bottom end fixed to the upper-middle portion of the fourth linkage component. The rear end of the third linkage component is fixed to the outer frame connecting component, and the rear end of the fourth linkage component is fixed to the wooden frame fixing component. The wooden frame fixing component is equipped with a position-limiting locking component, which is used to lock and fix the outer frame connecting component. A spring is fixed between the lower-middle end of the second linkage component and the bottom-middle end of the fourth linkage component. The sliding rail component is a grooved sliding rail, enabling the sliding wheels within the sliding rail component to roll back and forth, thereby driving the middle frame to move.

[0038] The front frame fixing component, first linkage component, second linkage component, third linkage component, fourth linkage component, sliding rail component, outer frame connecting component, and wooden frame fixing component together form the above linkage mechanism.

[0039] In some aspects, the front end, middle end, and rear end of a linkage device are respectively fixed with a front frame, a middle frame, and an outer frame. The front frame has four borders, within which several horizontal and vertical fixing components are secured inside the four borders. The front end of the front frame is fixed to the front wooden plate, while its middle and rear ends are secured to the fixing components of the front frame. The front and side ends of the middle frame are fixed to the inner side of the sliding rail component using sliding rail locking components, and its rear end is fixed to the front end of the outer frame using bolts. The rear ends of the outer frame are secured to wooden frame fixing components, which are fixed to the side wooden plate. The side wooden plate is mutually fixed to the rear wooden plate, with the front end of the side wooden plate fixed to a stabilizing wooden frame that secures both side wooden plates. The bottom left and right sides of the front wooden plate are equipped with foot nails, which are locked in place using L-shaped locking components.

[0040] In some aspects of the disclosure, the bottom inside of the first linkage component is fixed with a synchronous support rod, which secures the linkage devices on both sides, enhancing the stability of the sofa bed.

[0041] In some aspects, a linkage device is made of iron components. It includes a front frame fixing component, a first linkage component, a second linkage component, a third linkage component, a fourth linkage component, a sliding rail component, an outer frame connecting component, and a wooden frame fixing component. The various parts of the linkage device feature innovative designs. For example, the front frame fixing component has a bent L-shape, the first linkage component has an F-shape, the second linkage component has an arc-shaped, and the third linkage component is straight.

[0042] When the front frame fixing component is lifted and folded backward, the first and second linkage components fixed to the rear end of the front frame fixing component are raised. When these two components reach their highest position, the sliding rail component becomes parallel to the front frame fixing component and the third linkage component. The fourth linkage component serves as the primary fixing linkage, playing a key role in securing the entire linkage device. It fixes the rear ends of the first and second linkage components and the front end of the third linkage component to the front end of the fourth linkage component, for example, using bolts. The rear end of the fourth linkage component is fixed with the outer frame connecting component and the wooden frame fixing component.

[0043] When the front frame fixing component is extended outward to a 180-degree angle, the limiting locking components on the first linkage component and the wooden frame fixing component play a critical role by preventing further movement of the front frame fixing component and the outer frame connecting component. This ensures the linkage device remains fixed after unfolding to a certain position. Through the mutual fixation and support among the linkage components, the device achieves both folding and unfolding functions. The linkage device features a simple and innovative structure, strong stability, and convenient operation, enabling seamless transformation from a sofa to a sofa bed. The auxiliary design of the sliding rail is a standout feature, allowing the sliding rail wheels to operate within the rail for an effortless transition between sofa and sofa bed. This ease of use makes it suitable for all types of users.

[0044] Aspects of the disclosure also provide a novel foldable sofa bed, which includes the aforementioned linkage device, a front cushion, an inner cushion, an outer cushion, armrest cushions, and a cover cushion. The front cushion is fixed to the outside of the front frame and serves as the sofa bed's seat cushion. The inner cushion is fixed to the outside of the middle frame and functions as the inner backrest cushion for the sofa bed. The outer cushion is fixed to the outside of the outer frame, serving as the outer cushion of the sofa bed. The armrest cushions are fixed to the outer sides of the side wooden plates and are used as armrests when the sofa bed is folded into a sofa. The cover cushion is fixed to the outside of the front wooden plate and is used to cover the front part of the sofa bed. In some aspects of the disclosure, the lower part of the outer cushion can be sewn with a zipper, making the cushion cover easy to remove and install.

[0045] In some aspects, a foldable sofa bed includes the above linkage device, a front cushion, an inner cushion, an outer cushion, armrest cushions, and a cover cushion. These cushions can be made by sewing leather or fabric and foam together, and then directly upholstering them, achieving an integrated structure of the cushions and the sofa’s internal frame. The finished sofa bed is designed for easy conversion between sofa and sofa bed modes.

[0046] When the user lifts the bottom of the cover cushion of the sofa bed upward, the linkage device and the sliding rail within it enable the outer cushion and inner cushion to fold and transform into the sofa's backrest. The front cushion at the foot of the sofa bed can be flipped upward to serve as the sofa seat cushion. When the user pulls the cover cushion of the sofa bed forward, the sofa extends into the sofa bed configuration. At this point, the foot of the sofa bed unfolds forward, aligning the front cushion, inner cushion, and outer cushion in a straight line, completing the transformation into a sofa bed. As a sofa, it offers comfortable seating. As a sofa bed, it provides a comfortable sleeping experience that follows ergonomic principles.

[0047] Within the present disclosure, the word “exemplary” is used to mean “serving as an example, instance, or illustration.” Any implementation or aspect described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects of the disclosure. Likewise, the term “aspects” does not require that all aspects of the disclosure include the discussed feature, advantage or mode of operation. The term “coupled” is used herein to refer to the direct or indirect coupling between two objects. For example, if object A physically touches object B, and object B touches object C, then objects A and C may still be considered coupled to one another—even if they do not directly physically touch each other. For instance, a first object may be coupled to a second object even though the first object is never directly physically in contact with the second object. The terms “circuit” and “circuitry” are used broadly, and intended to include both hardware implementations of electrical devices and conductors that, when connected and configured, enable the performance of the functions described in the present disclosure, without limitation as to the type of electronic circuits, as well as software implementations of information and instructions that, when executed by a processor, enable the performance of the functions described in the present disclosure.

[0048] It is to be understood that the specific order or hierarchy of steps in the methods disclosed is an illustration of exemplary processes. Based upon design preferences, it is understood that the specific order or hierarchy of steps in the methods may be rearranged. The accompanying method claims present elements of the various steps in a sample order, and are not meant to be limited to the specific order or hierarchy presented unless specifically recited therein.

[0049] The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but are to be accorded the full scope consistent with the language of the claims, wherein reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more.” Unless specifically stated otherwise, the term “some” refers to one or more. A phrase referring to “at least one of” a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover: a; b; c; a and b; a and c; b and c; and a, b and c. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 U.S.C. §112(f) unless the element is expressly recited using the phrase “means for” or, in the case of a method claim, the element is recited using the phrase “step for.”