F type clamp having a locking function

An F type clamp, comprising:

• a base frame comprising a locating frame bar and a rail connected at right angles;
• a sliding member having one end thereof selectively shifted between an unlocking position where said sliding member is movable along said rail and a locating position where said sliding member is locked to said rail, said sliding member further comprising a locating screw hole disposed in communication with said through hole;
• a clamping member movably mounted at an opposite end of said sliding member remote from said rail, said clamping member comprising a jaw plate located at one end thereof for working with said locating frame bar to hold down a workpiece;
• and
• a locking device set between said sliding member and said rail for locking said sliding member to said rail under normal conditions and for enabling said sliding member to be moved relative to said rail by an external force, said locking device comprising a spring-loaded locking member and a screw member, with said spring-loaded locking member elastically stopped against an outer short side of said rail remote from said clamping member, and said screw member threaded in said locating screw hole and stopped at one end of said spring-loaded locking member against said rail, said screw member of said locking device further defining an accommodation hole in one end thereof for accommodating said locking member;
• said locking device further comprises a spring member accommodated in said accommodation hole and stopped between said locking member and said screw member,
• wherein said base frame further defines a vertical line extending along the length of said rail;
• said sliding member further comprises a first sidewall, a second sidewall opposite to said first sidewall, and a through hole cut through said first sidewall and said second sidewall for the passing of said rail, said through hole defining a central axis, said central axis defining with said vertical line a predetermined contained angle larger than zero angle so that said sliding member is unlocked from said rail and movable relative to said rail when said central axis and said vertical line are superimposed or kept in parallel, or locked to said rail when said central axis is biased relative to said vertical line.