Proportional control drive mechanism

A thermostatic assembly for use in a thermostatic valve assembly having a chamber, the thermostatic assembly comprising:

• a wax element;
• a ball valve component having a drive pin;
• and
• a plunger having a drive opening that is configured to receive the drive pin,
• wherein the drive opening defines a partially flattened oval profile with a first portion that defines a flat section with a curved turn at each end and a second portion that defines a curve that is connected at each of its ends to the first portion,
• wherein the plunger is connected to the wax element and slideably secured within the chamber and configured to move between a first linear position and a second linear position, and
• wherein the ball valve component is rotatably secured within the chamber and configured to move between a first rotational position when the plunger is in the first linear position and a second rotational position when the plunger is in the second linear position.

A plunger for use in a thermostatic assembly having a wax element and a ball valve component having a drive pin, the plunger comprising:

• a neck portion;
• and
• a body portion that defines a drive opening configured to receive the drive pin,
• wherein the drive opening defines a partially flattened oval profile with a first portion that defines a flat section with a curved turn at each end and a second portion that defines a curve that is connected at each of its ends to the first portion,
• wherein the plunger is connected to the wax element and slideably secured and configured to move between a first linear position and a second linear position, and
• wherein the plunger is configured to move the ball valve component between a first rotational position when the plunger is in the first linear position and a second rotational position when the plunger is in the second linear position.