Scotch yoke

A valve comprising:

• a. a scotch yoke having a hole therethrough, a threaded rod extending along an axis through said hole in a first direction, means for preventing said rod from moving in said first direction, a yoke arm in said housing pivotable about an axis and extending in a second direction that intersects said first direction, slot means in said yoke arm, a member on said rod and threadingly engaged therewith, said member having projection means extending through said slot means in said yoke arm, a means cooperating with said projection means for absorbing thrust in a sideward direction on said yoke arm and in a sideward direction on said rod, said means for absorbing thrust being positioned in a plane which includes said axis of said rod and is perpendicular to said sideward direction of said rod to thereby minimize bowing and twisting in said yoke arm and said rod, and a threaded hole extending through said member, said rod being threaded into said threaded hole, said means for absorbing sideward thrust to minimize bowing and twisting comprises a guide strap fixed to said housing and a saddle slidably mounted on said guide strap, said guide strap extending in said first direction, said projection means fitting into a hole in said saddle to link said saddle to said yoke arm, whereby rotation of said rod slides said member in said first direction and pivots said yoke arm about said axis;
• b. a valve body having a passage for fluid flow, a closure means for controlling flow therethrough and a shaft extending along said shaft axis and connected to said closure means;
• and
• c. actuator means for rotating said threaded rod to rotate said yoke arm and therefore said closure means.