SPRING-TOOTH HARROW Russian patent published in 2009 - IPC A01B19/02 

FIELD: machine building.

SUBSTANCE: proposed spring-tooth harrow consists of flat spring draw-bars and vertical cylindrical teeth attached thereto. The cylindrical tooth lower face is cut at 5-10° to horizontal plane, and attached to the round leg. The tooth vertical axis features a through hole with its diametre equal to that of the said leg. The latter enters the hole for the depth of G_h=2 to 3 D_t, where D_t is the tooth diametre. The tooth top features a blind hole arranged at the distance L_h.=1.618 d, where d is the leg diametre, from the tooth top edge and perpendicular to the vertical axis of tooth symmetry. Aforesaid hole receives attachment element to be threaded therein and made up of the upper threaded cylindrical and lower conical parts. The latter enters the appropriate conical hole made in the leg bottom. The length of the said attachment element is smaller than the round leg diametre. The tooth top features the outer surface groove arranged so that its horizontal axis of symmetry is aligned with the lengthwise axis of symmetry of aforesaid threaded blind hole. The top end face of the attachment element features the groove with its width and thickness those of the lock spring ring arranged in the groove, along the tooth outer surface. The tooth enters the attachment element groove. The taper of the attachment element lower end equals that of the round leg hole. The lengthwise axis of symmetry of aforesaid hole lies in parallel to the direction of motion. This hole is made on the tooth side opposite the direction of motion.

EFFECT: reduced forces of friction on teeth end faces, higher repairability.

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