Patent Application
20080084084
With reference to
The seat (45) has a bottom and two edges. The side frames (31) are connected respectively to and extend down respectively from the edges of the seat (45) parallel to each other. The braces (33) are connected respectively to the side frames (31), and each brace (33) has an outer end and an inner rear end. The outer ends are rotatably mounted respectively around the side frames (31).
The primary wheels (40) are rotatably connected respectively to the side frames (31). The secondary wheels (41) are connected respectively to the side frames (31) in the front of the primary wheels (40).
The longitudinal shafts (100) are hollow, are connected parallel respectively to the side frames (31) below the seat (45) and have a cross-section. The cross-section may be circular.
The cross-shafts (101) are hollow, are formed respectively with and extend perpendicularly respectively from the longitudinal shafts (100) and are pivotally connected respectively to the side frames (31) opposite to the longitudinal shafts (100). With further reference to
The mounting bracket (102) is U-shaped, is formed on and protrudes longitudinally from the distal end of the cross-shaft (101), is mounted around the side frame (31) and has two distal edges and multiple mounting holes (107). The mounting holes (107) are formed transversely through the mounting bracket (102) near the distal edges.
The proximal brackets (103) may be triangular and hollow, are mounted opposite to each other on the front and the rear of the cross-shaft (101) near the proximal end and are connected to the longitudinal shaft (100).
The distal brackets (104) may be triangular and hollow, are mounted opposite to each other on the front and the rear of the cross-shaft (101) near the distal end and are connected to the mounting bracket (102).
The medial pivot hole (105) is formed through the cross-shaft (101) from the front to the rear and aligns with the medial pivot hole (105) through the other cross-shaft (101).
The brace pivot hole (106) is formed from the front to the rear through the cross-shaft (101) between the medial pivot hole (105) and the proximal end of the cross-shaft (101), is connected pivotally to the inner end of the brace (33).
The pivot tubes are formed in the cross-shaft (101) between the front and the rear and are held respectively inside the medial pivot hole (105) and the brace pivot hole (106).
The supporting strut (10) is manufactured by a mold assembly with an upper mold and a lower mold. Each mold has a cave. In the manufacturing process, melted plastic material is led into the caves of the upper mold and lower mold, then a compressed inert gas (such as a nitrogen gas) is injected into the molds to blow the plastic material to form the hollow supporting strut (10) based on the shapes of the caves. Two posts are arranged in the molds to form the pivot tubes, the medial pivot hole (105) and the brace pivot hole (106).
With reference to
The supporting strut (10) as described has the following advantages.
1. The supporting strut (10) is plastic and is formed by molding. The supporting strut (10) can be mounted directly on the wheelchair without further processing, which will decrease the cost and time for manufacturing a supporting strut (10).
2. Since the supporting strut (10) is made of plastic, the supporting strut (10) is lighter than a conventional supporting strut (32) made of metal. Furthermore, the plastic supporting strut (10) will not rust so users will not need to paint the supporting strut (32).
3. The longitudinal shaft (100), the cross-shaft (101) and the mounting bracket (102) are molded as a single piece so no weakness will exist between pieces as a result of welding or otherwise connecting individual parts.
Even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and features of the invention, the disclosure is illustrative only. Changes may be made in the details, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.
