Abstract: A recirculating ball nut includes an inner hollow element surrounding a ball screw extending therethrough with the inner hollow element and the ball screw having cooperating helical grooves with balls therein. The ball nut has an outer hollow element surrounding the inner hollow element and secured thereto. The outer hollow element has the same number of helical grooves, which extend for less than a revolution, on its inner surface as the inner hollow element. Each helical groove in the outer hollow element has its ends communicate through ball connectors with one of the helical grooves in the inner surface of the inner hollow element and the cooperating helical groove in the ball screw at two spaced portions to allow the balls to recirculate. Each ball connector is disposed within a slot in an end of the inner hollow element and rests on an arcuate portion of an inner surface of the outer hollow element.

Abstract: A grinder has an abrasive belt removably mounted on a wheel for grinding a workpiece. The belt has its ends extend through a transverse slot in the wheel into a recess within the wheel. One end of the belt is attached to a first slider and the other end of the belt is attached to a second slider with the sliders increasing the tension on the ends of the belt through outward movement of the sliders by centrifugal force as the wheel rotates with the tension increasing as the angular velocity of the wheel increases. The sliders may move parallel to each other or along two separate radii extending from the axis of rotation of the wheel. Pivotally mounted pendulums may be employed instead of the sliders to apply tension to each end of the belt with the pendulums increasing the tension on the ends of the belt through outward movement of the pendulums by centrifugal force created by rotation of the wheel.

Abstract: A tailstock body of a numerically controlled lathe is positioned by a hydraulic rotary motor at a desired position to have a quill center of the tailstock body engage one end of a part or workpiece. The positioning of the tailstock body is by a programmable controller of a numerical control receiving signals for an encoder attached to the hydraulic rotary motor.

Abstract: A spindle carrier, which is movable vertically by an electric servo motor through a relatively long ball screw, has a substantially constant counterbalance force maintained on it irrespective of whether it is moving up or down. This prevents compression or tension of the ball screw. The counterbalance force is maintained substantially constant through sensing the load on the spindle carrier and using the sensed load to vary the hydraulic pressure applied to a piston within a hydraulic cylinder and connected through a chain to the spindle carrier to apply the counterbalance force.

Abstract: A distortable diaphragm seal, which is preferably formed of felt, seals each end of a nut through which a screw extends. Grease, which is introduced into the interior of the nut to function as a lubricant, is sealed therein by the seal. The seal has an opening of substantially the cross sectional shape of the screw normal to the axial centerline of the screw to permit part of the seal to extend circumferentially along the unthreaded O.D., and to permit another portion of the diaphragm seal to run into, and out of, a helical groove in the ball screw, thus forming a continuous seal on the screw surface.

Abstract: A thermal printhead, which is pivotally mounted on a carrier, is moved into and out of its printing position by a four bar linkage, which is responsive to the direction in which the carrier is being advanced, rendering a spring, which urges the thermal printhead into its printing position, effective and ineffective. When the carrier is advanced from left to right to print, the linkage responds to a drive mechanism for the carrier to enable movement of the printhead into its printing position by the spring prior to the carrier drive mechanism moving the carrier. When the carrier is to be moved from right to left in the non-printing direction, the linkage responds to the initial motion of the carrier drive mechanism in this direction to render the spring ineffective and to move the printhead out of its printing position prior to the carrier drive mechanism moving the carrier.

Abstract: A numerically controlled lathe has its tailstock body clamped on ways of a bed at a desired position by pucks through using an intensifier to increase the hydraulic pressure applied to the pucks to three times the hydraulic source pressure. The intensifier is automatically replenished with hydraulic fluid each time that there is release of the clamping pucks.

Abstract: Bore holes are formed in opposite side walls of a part in alignment with each other by two separate cutting tools in two separate machine tools disposed on opposite sides of the part. One of the machine tools is a master and the other is a slave with the master machine tool being disposed at the position at which it is to form a bore hole in one of the opposite side walls. Then, the slave machine tool is moved so that the longitudinal axis of its spindle is in alignment with the longitudinal axis of the spindle of the master machine tool whereby the two bore holes will be aligned with each other and extend through the entire part. This alignment is accomplished by a laser on a spindle carrier of the master machine tool producing a laser beam in parallel with the longitudinal axis of the spindle of each of the spindle carriers and being received by a laser target on the spindle carrier of the slave machine tool.

Abstract: Printing apparatus has an ink jet printhead mounted on a carrier for movement during printing of characters between left and right margin locations relative to a document. A directionally oriented grating and associated circuitry is provided to maintain a record of character and ink drop printing locations. The printhead begins its movement prior to the left margin location and sweeps toward the right margin for printing of an entire line of characters. Thereafter, the printhead is returned to the aforesaid position prior to the left margin in readiness for another line sweeping action. Provision is made for testing carrier velocities encountered in movement to the right during printing as well as to the left during carrier return and for determining optimum times of operation of the carrier return magnet and its release in order to reduce time required for carrier turnaround.