Hydrostatic pressure release apparatus for hydrostatic transmission

A method of adjusting a bypass valve of a hydrostatic transmission, comprising:

• providing a valve actuator comprising
• a release key elongated along an actuation axis and adapted to rotate about the actuation axis, the release key having
• an engagement feature adapted for operational engagement with the bypass valve of the hydrostatic transmission,
• a cylindrical exterior surface,
• a release key shoulder, and
• a release key stem having a flat thereon,
• a release mount defining a cylindrical interior surface mated to the cylindrical exterior surface and coaxial with the actuation axis, the release mount adapted to retain the release key in operational engagement with the bypass valve of the hydrostatic transmission while permitting the release key to rotate about the actuation axis,
• a spring operationally engaged between the release key shoulder and the release mount and adapted to bias the release key away from the release mount,
• a release lever
• elongated to define a first lever axis and second lever axis parallel to and offset from the first lever axis by a release lever operational length, and
• operationally engaged with the flat and operable to apply operational torque to the release key such that the first lever axis is coaxial with the actuation axis, and
• a release rod operationally engaged with the release lever at the second lever axis;
• operationally engaging the engagement feature with the bypass valve of the hydrostatic transmission;
• and
• using the release rod to adjust the release lever to apply operational torque to the release key to adjust the bypass valve.

A set of hydrostatic transmissions with a valve actuator comprising:

• a right hydrostatic transmission having a right bypass valve;
• a left hydrostatic transmission having a left bypass valve;
• a release key elongated along an actuation axis and adapted to rotate about the actuation axis, the release key having
• a right engagement feature operationally engaged with the right bypass valve and fixed to the release key to rotate therewith,
• the right engagement feature having
• a right cylindrical exterior surface,
• a right release key shoulder, and
• a right release key stem, and
• a left engagement feature operationally engaged with the left bypass valve and fixed to the release key to rotate therewith,
• the left engagement feature having
• a left cylindrical exterior surface,
• a left release key shoulder, and
• a left release key stem;
• a right release mount defining a right cylindrical interior surface mated to the right cylindrical exterior surface and coaxial with the actuation axis;
• a left release mount defining a left cylindrical interior surface mated to the left cylindrical exterior surface and coaxial with the actuation axis;
• a release lever
• elongated to define a first lever axis and second lever axis parallel to and offset from the first lever axis by a release lever operational length, and
• operationally engaged with the release key and operable to apply operational torque to the release key such that the first lever axis is coaxial with the actuation axis;
• and
• a release rod operationally engaged with the release lever at the second lever axis.