Abstract: A hitch assembly for towing a mower includes a tool bar, a first hitch member for mounting on the tool bar, a pivot pin extending from the mower for engagement by the hitch member, and a spring for exerting a lifting force between the pin and the hitch member to transfer a portion of the weight of the mower to the hitch assembly. The spring may be a tension spring extending between the pivot pin and an upper hitch portion to bias the pivot pin toward the upper hitch portion, or a compression spring captured between the hitch member and a spring seat to bias the pivot pin upward relative to the hitch member.

Abstract: A holographic apparatus uses electronically processed three-dimensional information about an object to produce a three-dimensional display of that object and its movement. A holographic screen has a plurality of angularly multiplexed holographic images which are selectively illuminated by a modulator and light source to produce the three-dimensional surface outline of the object to be seen. Color encoding and rapid sequential presentation of images gives the effect of a full-color, three-dimensional "television" in which movement of the object and both horizontal and vertical parallax can be provided.