Patent ID: 11864481
Assignee: nan
Field: Other special machines (Mechanical engineering)
Classification: CPC A | IPC A

Claim 0:
1. A harrow comprising:
a frame;
an array of tines pivotal about respective horizontal axes on the frame, the tines each having an upper arm extending upward from the respective axis above the axes and a lower arm extending downward from the respective axis and engageable with a soil surface under the harrow;
an extensible actuator above the axes on the frame;
a bar frame shiftable horizontally on the frame above the axes by the actuator; and
respective spring biasing units above the axes and each having
a guide element connected to the bar frame and displaceable therewith through a predetermined displacement path,
a connecting element connected to a respective one of the upper arms,
a first compression spring bearing on both of the elements and biasing the elements away from each other so as to press the lower arm downward into the soil surface during movement of the respective guide element through the path, and
a second compression spring bearing continuously on one of the elements and engageable with the other of the elements after displacement of the respective spring-biasing unit only through a part of the path.