Patent Publication Number: US-4321716-A

Title: Convertible seat-bed

Description:
SUMMARY OF THE INVENTION 
     The purpose of the invention is to improve upon the prior art by making a convertible seat-bed which has less weight and is more economical to manufacture. 
     A more specific object of the invention is to provide a construction wherein only simple linkage is used and incorporates important advantages including the coordinate movement of the seat and back such that the adjacent portions of the seat and back cushions in the seat and bed positions maintain a predetermined distance from each other. Also, because of the linkage used the top edge of the back cushion moves in an almost vertical path requiring very little clearance space away from an adjacent wall when moving from one position to another. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     FIG. 1 is a view of the convertible seat-bed in the seat or chair position. 
     FIG. 2 is a view of the convertible seat-bed in the bed position. 
     FIG. 3 is a partial view of the seat-bed illustrating an alternative construction of the guides in the supporting base. 
     FIG. 4 is a partial view of the seat-bed illustrating a link and guide means used in lieu of the seat supporting locking link shown in FIGS. 1 and 2. 
     FIG. 5 is a partial view of the seat-bed illustrating an alternative construction of the lazy tong like linkage. 
    
    
     Reference numeral 20 designates the convertible seat-bed of this invention. Seat-bed 20 may be used anywhere desired, however, the unit has special use in campers, vans and other recreational vehicles. In the drawing, reference numeral 21 indicates a wall and 22 a floor. Note that very little clearance is required between the back cushion 11 and wall 21 for movement of the back when moving from one position to another. This is achieved by using a lazy tong like linkage 8 which makes the top back edge of the back cushion travel in a vertical path. 
     A support for the seat-bed is constructed of a pair of U-shaped tubular members having their closed ends resting on floor 22. The pair of U-shaped members are connected by channel members 13 and 14. The top of one leg of one of the U-shaped members is connected to the top of the opposite one leg of the other U-shaped member by channel member 13. A corresponding connection by channel member 14 is made with the tops of the second legs of the pair of U-shaped members. Each U-shaped member has the upper portions of its legs connected by a flat member 2. 
     The rigidifying member 2 includes guides 3 and 4 having straight or curved grooves which may slope up towards the front of the seat-bed as illustrated in FIGS. 1 and 2. If desired the guides may be made level in member 2 as illustrated in FIG. 3. The sloping guides appear to give better seat movement and are preferred. 
     A first embodiment of the seat connecting linkage illustrated in FIGS. 1 and 2 show three links 5, 6 and 7 for supporting the seat support 9b which in turn supports a seat cushion 12. Link 5 pivotally connects the front of the seat support 9b to the front leg of the U-shaped frame or base. Link 6 pivotally connects the seat support to guide 4. Link 7 pivotally connects seat support to guide 3 and also to a link 8a. 
     A second embodiment of the seat support links is illustrated in FIG. 4. Here a third link 6a and guide 4a are used in lieu of the locking link 5 which is used in the first embodiment. 
     A lazy tong like linkage 8 (FIG. 1) controlling the movement of the back support, which is used to support back cushion 11, consists of three links 8a, 8b and 8c wherein links 8a and 8b are interconnected at an intermediate point. One end (top) of the link 8b is connected to back support 9a and the other end to the base 1. Link 8a besides being pivotally connected at its lower end to link 7, as previously mentioned, is at its other end pivotally connected to link 8c of whose top end is pivotally connected to back support 9a. 
     A second embodiment of the lazy tong like linkage illustrated in FIG. 5 shows a single link 8d and a grooved cushion support 9c used in lieu of the linkages 8a, 8c and cushion support 9a illustrated in FIG. 1. 
     If desired a torsion spring may be added to the pivot joint connecting levers 8a and 8c. One end of the spring would bear against lever 8a and the other end of the spring would bear against lever 8c such that when in the bed position the spring would be in a stressed condition. This feature could be used in any size seat-bed but would be of aid especially to the user of a large seat-bed assembly. 
     Although not shown it is contimplated that appropriate bearings would be used where needed. 
     With the arrangement thus far described and the seat-bed in the seat position as illustrated in FIG. 1, to convert to the bed position, the user pulls up and out on the seat. Note that the seat and back angles are such as normally found in the furniture art. Movement of the seat by the user in an up and out direction extends the seat to the bed position. During this movement linkages 6 and 7 cause the seat cushion to raise to a predetermined level with link 5 locking the seat in the bed position when the seat is extended. Lazy tong like linkage 8 operated by lever 7 causes the linkage 8 to collapse moving the top back edge of the back cushion 11 into a vertical downward path and at the same time causing the lower end of the cushion 11 to move in a following path with the seat cushion forming a bed therewith. In the bed position the seat support 9b will rest on channel 13 and the back support will rest on channel 14.