Abstract: A ball nut and screw assembly with a screw having exterior helical ball carrying groove portions separated by land portions and a co-axial nut having complemental, helical interior ball carrying groove portions separated by land portions with the same lead as said screw groove and land portions has, an end attachment for the nut with a reduced diameter sleeve extending axially therefrom. The sleeve has helical exterior thread portions, of the same lead as the nut groove portions, which are of a matching configuration and are threaded into one end of the nut. The sleeve has an interior diameter which receives and passes the screw without interacting with the screw. A recirculating train of load bearing balls is accommodated within nut and screw groove portions which are axially spaced from the sleeve.

Abstract: A ball nut and screw assembly has a backdrive control member that travels with the ball nut and has an internal thread complementary to and engaging the helical ball receiving groove on the screw. The backdrive control member is indexable on the screw relative to the ball nut to adjust the load of a spring that is interposed between the control member and ball nut. The spring acts to urge these components apart and thereby determine the frictional drag of the threaded engagement between the control member and the ball screw. The preload of the spring is set by indexing the control member to effect sufficient drag to prevent axial loads on the nut and screw from causing backdrive translation of the nut. The backdrive control member also removes lash from the ball nut and screw assembly under reversing loads at load magnitudes equal to or less than that produced by the load spring.

Abstract: A ball nut and screw assembly has a conventional helical raceway and balls received therein that react load through the centerline of the assembly and an added helical raceway and balls received therein that react radial load on the ball nut to the relief of the first mentioned raceway and balls.

Abstract: The present invention is a multiple range electronic weigh scale which employs a single load cell and selectable amplifier gain. A more sensitive range would employ a higher gain amplification than a less sensitive range. In accordance with the preferred embodiment, the amplified load cell signal is applied to an analog to digital converter and the digital output is applied to a microprocessor. The microprocessor enables selection between the weight ranges based upon the relationship of the digital output to upper and lower limit values. The microprocessor also generates the output weight signal for display based upon the product of the digital output and the selected gain. In a further embodiment the microprocessor generates a digital offset signal which is applied to the inverting input of a differential amplified via a digital to analog converter. This permits the starting point of the most sensitive range of the electronic weigh scale to be adjusted to any desired point in the higher range.