Abstract:
A stronger foldable bed having a frame and a foldably soft cover attached thereto. The frame has two pairs of side bars each pivotally connected to a central link, a tilt leg pivotally connected to a free end of each side bar, three pairs of scissoring end or middle bars linking the two pairs of side bars, a pair of middle leg each containing a telescoping leg, a reinforcing bar each pivotally connected to one side bar and a sleeve covering on each tilt leg, and a journey limit formed on each tilt leg. The foldable bed is longitudinal stable, simple and strong, without sacrificing the easiness of operation of folding and expanding.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a foldable bed, and more particularly, to a foldable bed with a simple yet strong structure which is able to be folded and expanded easily. 
     2. Description of the Prior Art 
     Shown in  FIG. 1  is a conventional foldable bed  8 . It has a foldable frame  81  and a soft cover  82  securely attached to the frame  81 . The foldable frame has a pair of middle legs  83 , and two pairs of end legs  84 ,  85 . One problem of such foldable bed is a longitudinally sway in direction A and B of the frame since the pairs of end legs  84 ,  85  lacks of a longitudinal reinforcing mechanism. 
     Another conventional foldable bed  9  shown in  FIG. 2  is more stable in terms of longitudinal sway since each pair of end legs  91  or  92  is reinforced with two pairs of tilt bars  93 ,  94 . However, aforementioned two conventional foldable beds  8  and  9  are either longitudinally unstable or complex in structure. Thus, it is desirable that there is provided a simple yet strong foldable bed without sacrificing the easiness of operation of folding and expanding. 
     BRIEF SUMMARY OF THE INVENTION 
     The main object of the invention is to provide a longitudinal stable foldable bed with simple yet strong structure but without sacrificing the easiness of operation of folding and expanding. 
     In order to accomplish the above objects, the present invention provides a foldable bed having a frame having:
         a first left side beam and a second left side beam pivotally connected to a left central link,   a first right side beam and a second right side beam pivotally connected to a right central link,   a tilt leg being respectively tilt to a free end of each the side beam and pivotally connected to each side beam near a free end of each side beam,   a first end bar pivotally connected to a free end of the first left side beam at one end thereof and to a free end of the tilt leg of an opposite side at a free end thereof,   an opposite first end bar pivotally connected to a free end of the first right side beam at one end thereof and to a free end of the tilt leg at a free end thereof, the first and the opposite first end bars being hinged at about middle portions hereof and able to scissor with respect to each other,   a second end bar being pivotally connected to a free end of the second left side beam at one end thereof and to a free end of the tilt leg of an opposite side at a free end thereof,   an opposite second end bar being pivotally connected to a free end of the second right side beam at one end thereof and to a free end of the tilt leg at a free end thereof, the first and the opposite second end bars being hinged at about middle portions hereof and able to scissor with respect to each other, a sleeve covering on and being slidable with respect to each the tilt leg,   a reinforcing bar pivotally connected to each the sleeve at one end thereof and to the side beam at a free end thereof at a position where between each the tilt leg and each the end bar being connected to each the side beam,   a journey limit securely formed on each the tilt leg under each the sleeve,   a middle leg of shape of a tube and fixed to each the central link,   a telescoping leg contained in each of the middle leg,   a foot installed at a free end of each the telescoping leg,   a middle bar pivotally connected to the left central link at one end thereof and to the foot of an opposite side at a free end thereof, and,   an opposite middle bar pivotally connected to the right central link at one end thereof and to the foot at a free end thereof, the middle bars being hinged at about the middle portion thereof and able to scissor with respect to each other; and,   a cover attached to the frame.       

     These and other objectives, features, and advantages of the present invention will become apparent from the following detailed description, the accompanying drawings, and the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view showing a conventional foldable bed. 
         FIG. 2  is a perspective view showing another conventional foldable bed. 
         FIG. 3  is a schematic perspective view showing the preferred embodiment of the foldable bed of the invention. 
         FIG. 4  is a schematic perspective view showing the foldable bed shown in  FIG. 3  with a soft cover thereof being removed. And, 
         FIGS. 5   a  to  5   c  is schematic views showing an operation of folding of the foldable bed shown in  FIGS. 3 and 4 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     With reference to  FIG. 3 , a perspective view of the preferred embodiment of a foldable bed  1  of the invention is shown. The foldable bed  1  is in a status of being expanded. The foldable bed  1  has a frame  2  and a soft cover  3  attached to the frame  2 . The cover  3  is foldably soft and so strong as being able to act as a bedplate when the foldable bed  1  is expanded. 
     As particularly shown in  FIG. 4 , the frame  2  has a first left side beam  20   a  and a second left side beam  20   b  pivotally connected to a left central link  21 , and a first right side beam  20   a ′ and a second right side beam  20   b ′ pivotally connected to a right central link  21 ′. 
     A tilt leg  22   a ,  22   a ′,  22   b , or  22   b ′, which is respectively tilt to a free end of each side beam  20   a ,  20   a ′,  20   b  or  20   b ′, is pivotally connected to each side beam  20   a ,  20   a ′,  20   b  or  20   b ′ near a free end of each side beam  20   a ,  20   a ′,  20   b  or  20   b′.    
     A first end bar  23   a  is pivotally connected to a free end of the first left side beam  20   a  at one end thereof and to a free end of the tilt leg  22   a ′ of an opposite side at a free end thereof. An opposite first end bar  23   a ′ is pivotally connected to a free end of the first right side beam  20   a ′ at one end thereof and to a free end of the tilt leg  22   a  at a free end thereof. The first and the opposite first end bars  23   a ,  23   a ′ are hinged at about the middle portion hereof and able to scissor with respect to each other. A second end bar  23   b  is pivotally connected to a free end of the second left side beam  20   b  at one end thereof and to a free end of the tilt leg  22   b ′ of an opposite side at a free end thereof. An opposite second end bar  23   b ′ is pivotally connected to a free end of the second right side beam  20   b ′ at one end thereof and to a free end of the tilt leg  22   b  at a free end thereof. The first and the opposite second end bars  23   b ,  23   b ′ are hinged at about the middle portion hereof and able to scissor with respect to each other. 
     A sleeve  24   a ,  24   a ′,  24   b , or  24   b ′ is provided covering on and being slidable with respect to each tilt leg  22   a ,  22   a ′,  22   b , or  22   b ′. A reinforcing bar  25   a ,  25   a ′,  25   b , or  25   b ′ is pivotally connected to each sleeve  24   a ,  24   a ′,  24   b , or  24   b ′ at one end thereof and to the side beam  20   a ,  20   a ′,  20   b , or  20   b ′ at a free end thereof at a position where between each tilt leg  22   a ,  22   a ′,  22   b , or  22   b ′ and each end bar  23   a ,  23   a ′,  23   b , or  23   b ′ being connected to each side beam  20   a ,  20   a ′,  20   b , or  20   b ′. A journey limit  29   a ,  29   a ′,  29   b , or  29   b ′ is securely formed on each tilt leg  22   a ,  22   a ′,  22   b , or  22   b ′ under each sleeve  24   a ,  24   a ′,  24   b , or  24   b ′ for blocking an over downward movement of each sleeve  24   a ,  24   a ′,  24   b , or  24   b′.    
     A middle leg  26  or  26 ′ is fixed to each central link  21  or  21 ′. Each middle leg  26  or  26 ′ is of a shape of a tube and contains a telescoping leg  27  or  27 ′ therein. A foot  271  or  271 ′ is installed at a free end of each telescoping leg  27 ,  27 ′. A middle bar  28  is pivotally connected to the left central link  21  at one end thereof and to the foot  271 ′ of an opposite side at a free end thereof. An opposite middle bar  28 ′ is pivotally connected to the right central link  21 ′ at one end thereof and to the foot  271  at a free end thereof. The middle bars  28 ,  28 ′ are hinged at about the middle portion thereof and able to scissor with respect to each other. 
     An operation of folding the foldable bed  1  of the invention is as shown in  FIGS. 5   a  to  5   c . For better illustration of movement of the frame  2 , the soft cover  3 , which will affect the operation of folding and expanding slightly, is not shown in these FIGs. With reference to  FIG. 5   a , in folding the foldable bed  1 , a user is able to move the left side beams  20   a  and  20   b  towards the right side beams  20   a ′ and  20   b ′. He may do this by either pulling the left and right central links  21  and  21 ′ towards each other with hands, or over turning the foldable bed  1  with the right side thereof laying on a floor and then pushing the left side thereof downward to the floor. 
     In whichever way, when the left side beams  20   a  and  20   b  move towards the right side beams  20   a ′ and  20   b ′, each pair of end bars  23   a  and  23   a ′,  23   b  and  23   b ′, and the middle bars  28  and  28 ′ scissor upward. Each tilt leg  22   a ,  22   a ′,  22   b , or  22   b ′ will rotate towards the side beam  20   a ,  20   a ′,  20   b , or  20   b ′ it pivotally connected to, and each sleeve  24   a ,  24   a ′,  24   b , or  24   b ′ will go upward toward each side beam  20   a ,  20   a ′,  20   b , or  20   b ′. Meanwhile, the telescoping legs  27 ,  27 ′ are pulled outward from the middle legs  26  or  26 ′. As shown in  FIG. 5   b , as the left side beams  20   a  and  20   b  arrive at a closest position to the right side beams  20   a ′ and  20   b ′, each tilt leg  22   a ,  22   a ′,  22   b , or  22   b ′ will arrive at a closest position to each side beam  20   a ,  20   a ′,  20   b , or  20   b ′ it linked. Then the user is able to fold the side beams  20   a ,  20   a ′,  20   b , or  20   b ′ towards the middle legs  26 ,  26 ′, to complete the operation of folding. A folded foldable bed  1  is as shown in  FIG. 5   c . A contrary operation may expand the foldable bed  1  of the invention for use. 
     From above description, it is seen that the objects of the present invention have been fully and effectively accomplished. Embodiment of the invention has been shown and described for the purposes of illustrating the functional and structural principles of the present invention and is subject to change without departure from the invention&#39;s principles. Therefore, this invention includes all modifications encompassed within the spirit and scope of the following claims.