Patent ID: 8220801

Claim:
A front mechanical seal assembly for pumps, comprising: a first collar adapted to mount to a shaft of the pump and having an inner face adapted to face toward the shaft and an outer face adapted to face away from the shaft; a second collar engageable with the first collar; a rotary seal rotatable in an axial direction thereof and mounted to the second collar; and at least one spring between the first and second collars and biasing against the second collar in the axial direction, wherein the first collar includes a recess portion on the outer face, a threaded hole, and at least one tightening pin arranged in the threaded hole, wherein the second collar includes a tongue that protrudes toward the recess portion in the axial direction and has a central hole for receiving the tightening pin, wherein said tongue is engageable in said recess portion to define a prismatic coupling between the first collar and the second collar, wherein, upon inserting the tightening pin into the central hole, said at least one tightening pin locks the second collar to the shaft of the pump, and wherein, upon inserting the tightening pin into the threaded hole, said at least one tightening pin locks the first collar to the shaft of the pump and the tightening pin does not interfere with the central hole so that the second collar is axially movable with respect to the first collar, wherein the second collar externally embraces the first collar and further includes an annular groove at the inner surface and at near an end of the rotary seal, wherein the first collar further includes a support ring received in the annular groove of the second collar for centering the second collar with respect to the shaft of the pump, and wherein the second collar further comprises another tongue adjacent to said tongue in a circumferential direction of the second collar and protruding toward another recess portion of the first collar in the axial direction.