Abstract:
A knee joint utilizes a shaft to dispose a rotating portion inside a body portion thereby enabling the body portion to rotate with respect to the shaft, the rotating portion being provided with a one-way bearing which enables the rotating portion to return rapidly to original position thereof in counterclockwise direction and utilizes a cushioning device and larger friction to cause the rotating portion to bend slowly in clockwise direction, thereby enabling people with disability to control and operate artificial limbs conveniently and easily.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention is related to a knee joint and in particular to one which can be rotated rapidly in one direction but slowly in the other. 
     2. Description of the Prior Art 
     It has been found that people with leg disabilities in society recently have been using artificial limbs to move, in order to facilitate their movements, thus enabling them to walk as if they have feet. Hence, various kinds of knee-joint structures for simulating the movement of the knee joint have been developed to meet the above-mentioned needs. However, the artificial limbs are mechanical structures, and require people with leg disabilities to move the thigh part of the leg in order to operate the artificial limb(s). The commonly used artificial limb includes an urging device which utilizes an axle to make it rotate with respect to a shaft. However, as the artificial limbs are not the real portion of a person&#39;s body, they are difficult to control and move smoothly. The artificial limbs are rotated too quickly when they are rotated in a walking movement. If the artificial limbs are turned excessively they will not be able to pass the urging sleeve, thereby making the artificial limbs move rapidly into a right angle. This creates a lack of support so that people with disabilities will fall down and injure themselves. Once the artificial limbs are bent at an angle, they cannot return to their original positions quickly, so that people with disabilities can only walk using small steps. Consequently, such conventional artificial leg joints are inconvenient and unsafe to use. 
     Therefore, it is an object of the present invention to provide an improvement in the structure of a knee joint which can obviate and mitigate the above-mentioned drawbacks. 
     SUMMARY OF THE INVENTION 
     This invention is related to an improvement in the structure of a knee joint. 
     According to preferred embodiment of the present invention, a knee joint utilizes a shaft to dispose a rotating portion inside a body portion thereby enabling the body portion to rotate with respect to the shaft, the rotating portion being provided with a one-way bearing which enables the rotating portion to return rapidly to original position thereof in counterclockwise direction and utilizes a cushioning device and larger friction to cause the rotating portion to bend slowly in clockwise direction, thereby enabling people with disability to control and operate artificial limbs conveniently and easily. 
     It is the primary object of the present invention to provide an improvement in the structure of a knee joint which can be rotated rapidly in one direction but slowly in the other direction. 
     It is another object of the present invention to provide an improvement in the structure of a knee joint which can be easily controlled to stop the rotation motion. 
     It is still another object of the present invention to provide an improvement in the structure of a knee joint which is simple in construction. 
     It is still another object of the present invention to provide an improvement in the structure of a knee joint which is safe in use. 
     It is a further object of the present invention to provide an improvement in the structure of a knee joint which can protect the user from injury. 
     The foregoing objects and summary provide only a brief introduction to the present invention. To fully appreciate these and other objects of the present invention as well as the invention itself, all of which will become apparent to those skilled in the art, the following detailed description of the invention and the claims should be read in conjunction with the accompanying drawings. Throughout the specification and drawings identical reference numerals refer to identical or similar parts. Many other advantages and features of the present invention will become manifest to those versed in the art upon making reference to the detailed description and the accompanying sheets of drawings in which a preferred structural embodiment incorporating the principles of the present invention is shown by way of illustrative example. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded view of the present invention; 
     FIG. 2 is a longitudinal sectional view of the present invention; 
     FIGS. 3 and 4 illustrate the working principle of the present invention; 
     FIG. 5 illustrates how to depress the button to stop the rotation motion; and 
     FIG. 6 is an exploded view of the rotating device. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     For the purpose of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings. Specific language will be used to describe same. It will, nevertheless, be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device, and such further applications of the principles of the invention as illustrated herein being contemplated as would normally occur to one skilled in the art to which the invention relates. 
     With reference to the drawings and in particular to FIG. 1 thereof, the knee joint according to the present invention basically utilizes a shaft  3000  to hold a rotating portion  2000  inside a body portion  1000 , so that the rotating portion  2000  can be turned with respect to the shaft  3000 . A sleeve  1100  is provided at the lower end of the body portion  1000  for holding a rod  6000  which is to be pivotally connected with ankle and sole. A cushioning device  5000  is pivotally connected with the body portion  1000  by a pin  5200  extending through a hole  1010  at the lower end of the body portion  1000 , so that the cushioning device  5000  can be rotated with respect to the pin  5200 . The other end of the cushioning device  5000  is rotatably connected with a rear end of the rotating body  2100  by a pin  5300  which extends through the holes  2110  of the rotating device  2100  and a hole  5010  of the cushioning device  5000 , so that when the rotating device  2100  is turned in clockwise direction (see FIG.  3 ), the cushioning device  5000  will slow the motion of the rotating device  2100  thereby preventing the user from unequilibrium and therefore keeping the user from danger. Further, an elastomer  5100  is fitted on the top of the body portion  1000  for absorbing the shock and impact produced when the rotating portion  2000  is returned. 
     A pivot portion  6100  is installed in the thigh of a user and a cover  4000  is engaged with the pivot portion  6100 . The cover  4000  is connected with the rotating device  2100  by a pin  5400  extending through a hole  2130  of the rotating device  2100 . 
     Referring to FIG. 2, a sleeve  2200  and a one-way bearing  2300  are fitted in the rotating device  2100  of the rotating portion  2000 , and two baffles  2400  and  2500  are mounted on two ends of the rotating device  2100 . The shaft  3000  extends through the body portion  1000  and the rotating device  2100  to engage with a screw  3100  so that the rotating device  2100  can be rotated with respect to the shaft  3000 . The baffles  2400  and  2500  are provided with bearings  2410  and  2510 , respectively, so as to smooth the rotation of the rotating portion  2000 . In addition, the upper of the cushioning device  5000  is provided with a bearing  5020  for smoothing the rotation of the cushioning device  5000 . 
     Referring to FIGS. 3 and 4, when the cover  4000  is turned with respect to the shaft  3000  to a position where the cushioning device  5000  cannot retract any more, the cushioning device  5000  can still decrease the rotation speed. Within the cover  4000  there is a screw  4100  which is engaged with a press rod  4200  so that the turning of the screw  4100  can adjust the position of the press rod  4200 . By means of the adjustment of the position of the press rod  4200 , the applied force can be adjusted. 
     As shown in FIGS. 5 and 6, the one-way bearing  2300  only rotates in one direction only so that only when the rotating portion  2000  is rotated counterclockwise will the bearing  2300  rotate. When the rotating portion  2000  is turned clockwise, the one-way bearing  2300  cannot be rotated so that the outer surface  2310  of the one-way bearing  2300  will be rotated in unison with the rotating portion  2000 . As the outer surface  2310  of the one-way bearing  2300  is rotated inside the sleeve  2200 , the friction therebetween will be increased thus causing the rotating portion  2000  to rotate rapidly in counterclockwise direction but rotate slowly in clockwise direction. In addition, the rotating device  2100  is formed with an orifice  2120  on the top in which is fitted a button  2600 . As the button  2600  is depressed, the clearance  2220  of the sleeve  2200  will be decreased thereby increasing the friction between the outer surface  2310  of the bearing  2300  and the inner surface  2210  of the sleeve  2200  thereby braking the rotation motion. Hence, it is only necessary to apply a small amount of force to stop the motion. Except in the position where it is impossible to depress the button  2600 , the user can stop the rotation motion even if the angle exceeds an angle of 30 degrees. 
     It will be understood that each of the elements described above, or two or more together may also find a useful application in other types of methods differing from the type described above. 
     While certain novel features of this invention have been shown and described and are pointed out in the annexed claim, it is not intended to be limited to the details above, since it will be understood that various omissions, modifications, substitutions and changes in the forms and details of the device illustrated and in its operation can be made by those skilled in the art without departing in any way from the spirit of the present invention.