GB1266811A - - Google Patents

Abstract

1,266,811. Cutting tools. K. HERTEL. 13 Jan., 1970 [13 Jan., 1969; 2 July, 1969; 16 July, 1969], No. 1716/70. Heading B3T. A lathe tool comprises a holder 1 and a releasable cutting insert 2 the insert being constituted by a body having side faces 9 which have the outline in the shape of a geometric combination of an isosceles trapezium 10 surmounted by an isosceles triangle 12 the common juncture between these figures being the base of the triangle and a cutting edge 21 being defined by the junction between each upper face and an adjacent end face 18, 19. A portion of the side faces converge towards one another away from the upper faces to provide side clearance angles of the insert and the intermediate portions of each side face are parallel. The insert 2 is located on a seating 8 at the end 7 of the holder 1 and is secured thereon by a clamping element 4 which acts on the upper face 17 of the insert remote from the operative cutting edge, the clamping element being retained by a screw 5. An abutment member 3 is provided in the holder 1 against which an end of the insert bears, the member 3 may be in the form of a screw with an eccentric head to permit longitudinal adjustment of the insert on the holder prior to clamping. In one alternate form of insert there is provided a recess at the juncture between the two upper surfaces 16a and 17 and an annular, 44, 45, or bevelled, 68, surface is provided at each end of the insert to form clamping surfaces for an alternative hook-like clamping member. The side of the insert may be alternately relieved to provide a narrow cutting edge at each end and the sides may be longitudinally offset whereby the cutting edges at each end are inclined in a longitudinal plane to the side faces. Alternative forms of back abutment members are described and may take the form of a notched bar member secured in the holder body or a screw member having a V notch in an axially bored head into which the inoperative end of the insert is located.