hinge 42 because the outer side wall terminates above the lower end of the clevis hinges 42 the bores in the lower end of the clevis hinges pass only through the inner side wall the bores in the lower ends of the clevis hinges 42 register with bores formed laterally through lower depending legs 48 shown on the elongate member 41 pins 46 project through the registered bores in the respective lower ends of the clevis hinges 42 and the lower depending legs 48 from the elongate member 41 thus strategically providing the bores for insertion of the pins 44 46 enables articulated movement of the main body of the top drive assembly 10 from the torque restraint 25 by pivoting of the linkage members 36 41 schematically illustrated in fig4 is a partial sectional view of the coupling between the torque restraint 25 and motor housing 27 by the clevis hinges 42 in optional embodiments the coupling of fig4 represents the connection between the clevis hinges 42 and the members 36 or member 41 respectively by pins 44 46 further illustrated in fig4 are strain gauges 52 for measuring strain within the pins 44 46 optional bores 54 are shown through the pins 44 46 through which a counter pin or other lynch type pin not shown is inserted to retain the pins 44 46 within the pivoting coupling the strain gauges 52 measure strain through bending moment in the pins.