Alternate walker having extensible/contractible front and rear legs

Claim 1

An alternate walker, comprising: a pair of reverse U-shaped frame pipes situated parallel to each other, each frame pipe having front and rear lower portions, cross bar means connected to the respective frame pipes to connect the same together, a pair of front legs, each partly slidably inserted into the front lower portion of the frame pipe, a pair of rear legs, each partly slidably inserted into the rear lower portion of the frame pipe, a pair of connecting means, each connecting means being slidably situated inside the frame pipe to connect between the front and rear legs so that when one of the front and rear legs is moved, the other is moved in association therewith, each connecting means including a plurality of substantially spherical bodies arranged in series to allow the adjacent spherical bodies to pivot relative to each other, a pair of control means attached to the frame pipes respectively, each control means including a pressing member, at least one guide member connected to the pressing member to allow the pressing member to move relative to the frame pipe, two control pins connected to the guide member to extend toward the pressing member, at least one spring device situated between the pressing member and the frame pipe to urge the pressing member to move away from the frame pipe, and four holes formed in the frame pipe to permit the control pins to enter thereinto so that when the two control pins are located in the holes, the control pins are situated between the adjacent two spherical bodies to thereby prohibit movement of the front and rear legs relative to the frame pipe, and when the pressing member is pushed relative to the frame pipe against force of the spring, the control pins move away from the holes to thereby permit movement of the front and rear legs relative to the frame pipe.