Patent EA-003340-B1 (EA)
Title: Working tool with replaceable working bit
Inventor: SKJAEVELAND MAGNE
IPC: A01B/
Filed: 2001-01-31
Abstract: 1. A replaceable wear part (13, 22, 22a, 32, 41) for mounting on a leading edge (12, 27) of a working tool (10, 27, 30), said leading edge and said wear part having cooperative guide formations (16, 18) extending generally perpendicular to the leading edge and which provide a socket and projection type of slidable inter-fit whereby the wear part can be driven by a force extending generally perpendicular to the leading edge in order to take-up a working position in which it is secured against displacement from the working position by frictional inter-engagement between the guide formations (16, 18) on the wear part and the leading edge, and without need for threaded or other separate removable fasteners, said co-operative guide formations (16, 18) allowing the wear part (13) to slide in a direction generally perpendicular to the leading edge (12), and a wedge-type inter-engagement between the guide formations (16, 18) being such that the greater the distance travelled, the stronger will be the frictional engagement forces acting between the guide formations, characterised in that the guide formations are defined by walls or faces (16, 18) which are of matching V-shaped in cross section to oppose relative rotation of the wear part (13) about its longitudinal axis (19). 2. A replaceable wear part according to claim 1, characterised in that in combination with a working tool, in which the socket is defined between a pair of opposed side walls (16) which are convergent or taper, and the wear part (13) has opposed external side faces (18) which are also convergent or taper, but to a lesser extent than the tapering of the side walls (16) of the socket, so that an increasing wedging force is generated therebetween as the wear part (13) is drive to its working position, whereby also the frictional resistance against possible displacement increases progressively. 3. A replaceable wear part according to claim 1, characterised in that in combination with a working tool, in which the socket is defined between a pair of opposed side walls (16) which are convergent or taper, and the wear part (13) has opposed external side faces (18) which are also convergent or taper, but to a great extent that the tapering of the side walls (16) of the socket, so that an increasing wedging force is generated therebetween as the wear part (13) is driven to its working position, whereby also the frictional resistance against possible displacement increases progressively. 4. A replaceable wear part according to any one of claims 1 to 3, characterised in that adapted to be mounted on a transversely extending leading edge of an agricultural tool, such as a point (30), a ploughshare (10), a cultivator tine (27), or a holding portion (27) of an agricultural tool. 5. A replaceable wear part according to claim 4, characterised in that the guide formations of the wear part (13) are V-shaped and provided on opposite edges of the projecting mounting portion of the wear part (13). 6. A replaceable wear part according to any one of the preceding claims, and comprises a main holder (40) which is detachably securable to a tine (42), and to which a point (41) is detachably secured, and in which the holder (40) comprises two parts, namely a main holder part (43) and a rear / upper holder part (44) which can be fastened to the tine (42) via a single fastener (45), and which has a tongue and groove type of inter-fit (46, 47) with the main holder part (40) to prevent rotation about the fastener, said rear / upper holding part also serving to act as a wear protecting plate for the tine.