DRAW HOOK OF HITCH ATTACHMENT, MAINLY FOR DRAFT ARMS OF THREE-POINT HITCH ATTACHMENT OF TRACTOR Russian patent published in 2014 - IPC B60D1/04 A01B59/00 

FIELD: machine building.

SUBSTANCE: draw hook of a hitch attachment comprises a casing including an opening for receiving and fitting a draft support of an implement, coaxial through holes for a blocking pin installation, and a cavity. A locking mechanism in the form of a catch which is spring-loaded to the direction of the opening is mounted in the cavity. The catch is coupled with a handle and set pivotally able of turning between supporting surfaces made in the upper part of the said cavity. The locking mechanism is fitted with upper and lower lugs which are set in a telescope manner, are pivotally attached to the catch and the hook casing respectively. The catch is made solid with the handle. The coaxial through holes are set in the zone of the handle movement, and the spring is installed between the said lugs and coaxial to them. The hinge of the upper lug is set on the catch so that when the draw hook is in the closed position, the spring axis is set between the opening and the plane passing through the lower lug hinge axis and the catch hinge axis, and when the draw hook is in the open position, the spring axis is set between the said plane and the handle.

EFFECT: simplified design of a draw hook and improved reliability due to decreased friction members and supporting surfaces of a catch.

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