Mechanical shaft seal

Claim 1

A mechanical seal for pumps and the like fluid containing, rotary shaft devices having a housing defining a fluid chamber closed about the shaft end, said seal of the class sealing the fluid in said chamber at a radial, rotary-stationary seal member contact interface and comprising, in combination: a rotationally stationary, axially movable seal sleeve to be received within said housing and over said rotary shaft end; means for circumferentially sealing between said seal sleeve and said housing; housing-carried bearing means located axially outwardly of and opposite to said seal sleeve; axially disposed, circumferentially balanced spring means engaged between said seal sleeve and bearing means, said spring means resiliently biasing said seal sleeve axially inward; a radial end face on the inner end of said seal sleeve said end face constructed and arranged as a right angularly disposed, precision lapped surface for engagement at said contact interface; an axially stationary, rotationally movable seal ring received over said shaft end inwardly of said seal sleeve, said seal ring having an inside diameter conforming to the shaft outside diameter to within a tolerance fitting the ring snugly to while allowing it to slide readily over the shaft end; means establishing a fluid tight seal between said seal ring and shaft end; an annular, reduced, stem extension integrally formed on said seal ring, said stem extension projecting axially inwardly of the main body of said seal ring and having an inner wall continuous with the inner wall of said main body of said seal ring; a taper formed on the outside of said stem extension and thickening that from the end toward the root thereof; thread forming means spirally serrating said taper; spaced, axial, kerf formations axially recessing said stem extension and dividing that into spring finger segments; a radial end face on the outer end of said ring, said end face constructed and arranged as a right angularly disposed, precision lapped surface for engagement at said contact interface; an integral, rigid, relatively narrow clamping ring; and thread forming means spirally serrating the inner wall of said clamping ring, said seal ring and clamping ring thread forming means mated one to the other, and said clamping ring having an inside diameter fitting the outside diameter of said stem extension at the outer extremities of said spring fingers when relaxed, whereby the winding of said clamping ring on said stem extension serves to radially contract said spring fingers to rigidly clamp said seal ring to said shaft without disaffecting its alignment therewith.