Patent Publication Number: US-2010113237-A1

Title: Inflatable shaft

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to an inflatable shaft, particularly to one able to keep a stuff directly wound around after the inflatable shaft is inflated and easily separated from the wound stuff after deflated, needing to use no additional shaft, not only lowering manufacturing cost but also amiable to environment. 
     2. Description of the Prior Art 
     Commonly, a stuff (A), such as shrinking film, packaging film or winding film etc., is wound around a tube  10  inserted with a conventional inflatable shaft  1 . The tube  10  is made of paper or plastics etc. With the inflatable shaft  1  installed and inflated on a winding device, the tube  10  can be driven to rotate to wind up the stuff (A). As shown in  FIGS. 1 and 2 , the conventional inflatable shaft  1  is provided with a tubular main body  11 , an air bag  12  installed inside the main body  11 , a plurality of inner pressing boards  13  attached to the outer wall of the air bag  12 , a space  14  formed between the pressing boards  13  and the main body  11 , a plurality of outer pressing boards  15  attached to the outer wall of the main body  11 , and a plurality of connecting bars  16  penetrated through the main body  11  to connect the inner pressing boards  13  with the outer pressing boards  15 . In using, the inflatable shaft  1  is inserted in the tube  10  and the air bag  12  is inflated to expand outward. By the time, the inner pressing boards  13  are squeezed to move outward to approach the main body  11  so as to push outward the outer pressing boards  15  moving away from the outer wall of the main body  11  to approach the inner wall of the tube  10 . So, the tube  10  is closely attached by the inflatable shaft  1  inflated, able to be driven by the inflated shaft  1  to rotate so as to make the stuff (A) wound around it. However, the tube  10  is to be dumped after the stuff (A) is used up, posing waste of source and ecological contamination. If the stuff (A) is to be directly wound around the air expanding shaft I instead of the tube  10  for environmental amiability, it is to sink into gaps (B) (as shown in  FIG. 3 ) created between every two adjacent outer pressing boards  15  while inflating the inflatable shaft  1 , formed with an unsmooth surface. When the inflated shaft  1  is deflated, the stuff (A) sinking in the gaps (B) is to be clamped by the outer pressing boards  15  because of shrinkage of the gaps (B), keeping the stuff (A) uneasy to be separated from the deflated shaft  1 . It is obvious that the process of directly winding the stuff (A) around the inflatable shaft  1  is absolutely not good. 
     SUMMARY OF THE INVENTION 
     The object of this invention is to offer an inflatable shaft able to keep a stuff directly wound around with the inflatable shaft inflated and easily separated from it with the inflated shaft deflated, not needing to use an additional shaft, not only lowering manufacturing cost but also amiable to environment. 
     The inflatable shaft of the invention is characteristically provided with a rubbery sleeve mounted around the outer wall of its outer pressing boards. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       This invention is better understood by referring to the accompanying drawings, wherein: 
         FIG. 1  is cross-sectional view of a conventional inflatable shaft; 
         FIG. 2  is cross-sectional view of the conventional inflatable shaft, showing it being inserted in a tube that is wound with a stuff after having the inflatable shaft inflated; 
         FIG. 3  is cross-sectional view of the conventional inflatable shaft, showing it inflated and directly wound with the stuff; 
         FIG. 4  is an exploded perspective view of a preferred embodiment of an inflatable shaft in the present invention; 
         FIG. 5  is a perspective view of the preferred embodiment of an inflatable shaft in the present invention; 
         FIG. 6  is a cross-sectional view of the preferred embodiment of an inflatable shaft in the present invention, showing it not inflated yet; 
         FIG. 7  is a cross-sectional view of the preferred embodiment of an inflatable shaft in the present invention, showing it wound with the stuff after inflated; and 
         FIG. 8  is a cross-sectional view of the preferred embodiment of an inflatable shaft in the present invention, showing it deflated after wound with the stuff. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     As shown in  FIGS. 4˜6 , a preferred embodiment of an air expanding shaft  2  in the present invention is provided with a tubular main body  20 , an air bag  21  installed inside the main body  20 , a plurality of inner pressing boards  22  attached to the outer wall of the air bag  21 , a space  23  formed between the pressing boards  22  and the main body  20 , a plurality of outer pressing boards  24  attached to the outer wall of the main body  20 , a plurality of connecting bars  25  penetrated through the main body  20  to connect the inner pressing boards  22  with the outer pressing boards  24 , and a rubbery sleeve  26  mounted around the outer pressing boards  24 . 
     In using, as shown in  FIG. 7 , when a stuff (A) is to be wound around the inflatable shaft  2 , the air bag  21  must be first inflated to expand outward so as to also push outward the inner pressing boards  22 , which are to successively approach the main body  20  and push outward the outer pressing boards  24  by means of the connecting bars  25 . By the time, the outer pressing boards  24  are to be separated from the outer wall of the main body  20  to enable the rubbery sleeve  26  squeezed to expand outward. The stuff (A) can thus be wound around the inflatable shaft  2  inflated. Next, as shown in  FIG. 8 , while the stuff (A) is to be separated from the inflated shaft  2  after wound with a desired thickness, the air bag  21  of the inflated haft  2  is deflated first to shrink inward. The inner pressing boards  22  resting on the air bag  21  are simultaneously moved inward to keep the space  23  between the inner pressing boards  22  and the main body  20  widened. And, by means of the connecting bars  25 , the outer pressing boards  24  are to be also forced to move inward to attach to the outer wall of the main body  20  again, so that the rubbery sleeve  26  is to shrink inward to create a space (C) between itself and the stuff (A). Therefore, the stuff (A) well wound without an additional tube can be easily separated from the deflated shaft  2 . 
     It is to be noted that, with the rubbery sleeve  26  mounted around the outer pressing boards  24  to expand outward while inflating the air bag, the gaps (B) formed among the outer pressing boards  24  are covered by the rubbery sleeve  26  that can be wound with the stuff (A) smoothly without having the stuff (A) sunk into the gaps (B) and clamped by the outer pressing boards  24  as happening in the conventional inflatable shaft. And, as the rubbery sleeve  26  can follow the outer pressing boards  24  to shrink inward while deflating the air bag  21 , the space (C) is to be formed between the rubbery sleeve  26  and the wound stuff (A) to enable the stuff (A) easily separated from the deflated shaft  2 . Therefore, by means of the inflatable shaft  2  of the invention, the stuff (A) can be smoothly wound without using an additional tube, not only lowering manufacturing cost but also amiable to environment. 
     While the preferred embodiment of the invention has been described above, it will be recognized and understood that various modifications may be made therein and the appended claims are intended to cover all such modifications that may fall within the spirit and scope of the invention.