Hinged joint for attachment of implements to agricultural tractors

Claim 2

A hinged joint particularly for a hinged coupling for attaching implements to agricultural tractors, comprising monolithic male and female elements having cooperating spherical surfaces, the female element having a circular entry aperture for the insertion of the male element into the female element, and the male element having parallel flat faces bounding its curved surface wherein the improvement consists in the curved surface of the male element comprising a spherical surface portion and a cylindrical surface portion, the axis of said cylindrical portion being parallel to the flat faces of the male element and passing through the centre of the spherical surface portion, and the cylindrical surface portion having a diameter just smaller than that of the said entry aperture.

Claim 3

The hinged joint defined in claim 1, wherein the said axis of the cylindrical surface portion is equidistant from the flat faces of the male element.

Claim 4

The hinged joint defined in claim 1 wherein the male element has at least one cylindrical surface bounding the entry aperture therein.

Claim 5

The hinged joint defined in claim 3, wherein the male element has two coaxial cylindrical surfaces bounding the entry aperture and having different diameters, the cylindrical surface nearer the spherical surface of the female element having the smaller diameter.

Claim 6

The hinged joint defined in claim 1 including means for retaining the male element in the female element.

Claim 7

The hinged joint defined in claim 5, wherein said retaining means comprise means defining a first circular groove in the entry aperture of the said female element and a second groove adjacent one of the intersections of the spherical and cylindrical surface portions of the male element, whereby after a relative rotation of the two elements has taken place the two grooves are disposed in register with one another, and including a circular expansion spring housed normally in the first groove and transferable from one groove to the other, whereby when the spring is in the first groove it blocks removal of the male element from the female element while when the spring is in the second groove such removal of the male element is possible.

Claim 8

The hinged joint defined in claim 1, wherein the female element has two parallel flat faces bounding the spherical surface of the female element said flat faces being separated from each other by a shorter distance than the width of the male element between the two flat parallel faces bounding the curved surface of the latter.

Claim 9

The hinged joint defined in claim 7, wherein the distance between the two flat faces which limit the spherical surface of the female element is smaller than the width of the male element belonging to the class of similar joints of smaller size.

Claim 10

A hinged three point coupling for attaching agricultural implements to an agricultural tractor including two lower arms each having a hinged joint for attachment of an implement, the hinged joint comprising monolithic male and female elements having cooperating spherical surfaces, the female element having a circular entry aperture for the insertion of the male element into the female element, wherein the improvement consists in the curved surface of the male element comprising a spherical surface portion and a cylindrical surface portion the axis of said cylindrical portion being perpendicular to the axis of the entry aperture and passing through the centre of the spherical surface portion, and the cylindrical surface portion having a diameter just smaller than that of the said entry aperture.

Claim 11

A hinged three point coupling for attaching agricultural implements to an agricultural tractor including two lower arms each having a hinged joint for attachment of an implement, the hinged joint comprising monolithic male and female elements having cooperating spherical surfaces, the female element having a circular entry aperture for the insertion of the male element into the female element, wherein the improvement consists in the curved surface of the male element comprising a spherical surface portion and a cylindrical surface portion the axis of said cylindrical portion being perpendicular to the axis of the entry aperture and passing through the centre of the spherical surface portion, and the cylindrical surface portion having a diameter just smaller than that of the said entry aperture.

Claim 12

The hinged coupling defined in claim 9, wherein the entry apertures in the two joints on the lower arms are defined by respective cylindrical surfaces and face in opposite directions.