Driving machine including speed synchronized earth working traction wheel

A public works machine comprising:

• a frame;
• moving members, such as wheels or caterpillar tracks, on which said frame rests for forward movement on the ground,
• drive means coupled to said moving members for driving said moving members,
• a traction wheel provided with a plurality of teeth for penetration into the ground mounted for rotation about a substantially horizontal rotational axis extending transversely to the frame and the direction of travel of the machine, said traction wheel being coupled to power transmission means for drivingly rotating said traction wheel in the same direction as, and in constant speed synchronization with, said moving means to provide a reactive force between a leading face of each tooth of the traction wheel and the earth tending to cause forward movement of the machine, said traction wheel being positionable with respect to the frame by means of a support in a position in which the distance between the rotation axis of said traction wheel and the ground is less than the distance separating the rotation axis from the outer end of each tooth of the traction wheel, said power transmission means including synchronizing means for maintaining the ratio of the speed of rotation of the traction wheel to the speed of the moving members at a constant value so that the outer end of each tooth of said traction wheel has a linear speed which is substantially equal to the linear speed of forward movement provided by said moving members, wherein each tooth had a leading face and a trailing face with respect to its rotational movement and the profile of the leading face of each tooth is an involute profile resulting in a minimum amount of vertical force being exerted by said profile on the ground during the rotation of the wheel and penetration of the earth by each respective tooth so as to minimize the power required for penetrating the earth by each tooth.