Abstract: A zero turning radius vehicle is disclosed having a power transmission operatively and independently engaged to each one of at least two driven wheels, and including at least one caster, supporting a portion of said vehicle weight, rotatably connected to the vehicle whereby the caster is operatively biased while the vehicle is operating at a side angle such that the caster neutralizes the gravitational force that would tend to drive the vehicle downward when traversing a slope.

Abstract: A zero turning radius vehicle is disclosed having a power transmission operatively and independently engaged to each one of at least two driven wheels, and including at least one caster, supporting a portion of said vehicle weight, rotatably connected to the vehicle whereby the caster is operatively biased while the vehicle is operating at a side angle such that the caster neutralizes the gravitational force that would tend to drive the vehicle downward when traversing a slope.

Abstract: In a bag making machine the longitudinal side edges and adjacent portions of an elongate plastic web, which is folded in half medially of its centerline, pass from a set of inlet rolls over and under, respectively, a pair of vertically spaced separating rolls before merging at a set of outlet rolls. The separating arms extend inwardly between the two separated portions of the web only part way toward the fold line, and are spaced apart exactly twice the depth of the gusset that is to be formed.

Abstract: The two separable elements of a conventional plastic zipper are advanced through a zipper guide slot from the inlet to the outlet end of a machine, simultaneously with two sections of a plastic film or web, one section of which overlies one of the zipper elements, and the other section of which overlies the other zipper element. Intermittently two jaws are advanced toward the web sections to squeeze them against opposite sides of the zipper, at which time a pair of registering hot bars that are resiliently mounted on the jaws adjacent the inlet end of the machine fuse each web section to a different one of the two zipper elements. At the same time, a pair of cold bars carried by the jaws adjacent the outlet end of the machine engage and cool portions of web sections which were previously fused to the two zipper elements. Idler rolls inclined to the zipper guide slot retain the folded web tautly over opposite sides of the zipper guide slot.

Abstract: Fluid under pressure, such as compressed air, is applied to one end of an elongate, thin, tubular plenum, the opposite end of which exhausts to the atmosphere. The plenum has intermediate its ends a plurality of axially spaced exhaust ports, which are connected to a valve mechanism having a rotary or reciprocable valve stem, which can be adjusted selectively to connect any one of the plenum exhaust ports through a single output port to a pneumatically operated device. The pressure of the air traveling through the plenum drops at a substantially linear rate, so that the pressures at the spaced exhaust ports can be plotted against the respective distances of these ports from the inlet end of the tubular plenum, thereby to provide a curve which can be used for predicting the pressure at any given point along the length of the plenum.