inches. Regardless of the roller spacing peculiar to a par- ticular  industry  or  application,  the  roller  spacing  in anythere  exists  a  need   for  a  roller   conveyor adjustable in length and that is adapted for   the particular power roller conveyor is typically  fixed.

A typical module of a power roller conveyor includes at least one drive roller and a plurality of “driven” rollers. In some instances, the drive roller is mechanically linked to a motor through, for example, a belt, chain or drive shaft so that the motor can selectively rotate the drive roller. In other, typically more modern, configurations, the drive roller typi- cally contains the motor internally. Driven rollers are mechanically linked to the drive roller, either directly or through intervening driven rollers, by belts or “o-rings,” for example. FIG. A illustrates a typical arrangement of driven rollers in relation to a single drive roller from which the driven rollers draw power. It is common for the drive roller to be among the central rollers along a power roller conveyor module because such an arrangement centers the torque transmission to the driven rollers.

Power roller conveyors are used to transport objects (e.g., mail piece trays) from one location to another within a mail-processing facility, for example. Frequently, an overall conveyor system comprises numerous roller conveyor mod- ules linked in series. A single roller conveyor module can be used to join one roller conveyor segment to another roller conveyor segment, a roller conveyor segment to a piece of processing equipment or one piece of processing equipment to a second piece of processing equipment, for example. Typically, roller conveyor modules are fabricated in fixed lengths correlating to some whole-number multiple of the fixed roller spacing plus some constant. Difficulties arise, for example, as equipment is replaced and the spacing between a replacement piece of equipment and another fixed point within the facility is not equal to the distance between the replaced piece of equipment and the fixed point or, worse, does not correspond to a whole-number multiple of the fixed roller spacing plus the original constant. Consider the sche- matic illustration of such a scenario in conjunction with FIGS. B and C. In the original arrangement of FIG. B,  first

selective addition and removal of rollers as indicated by a particular  situation.

SUMMARY：In various embodiments, an adjustable roller conveyor module includes a roller support structure having first and second ends and first and second laterally spaced, elongated frame members arranged in parallel and extending between

40 the first and second ends along a central longitudinal axis. Extending between, and supported by, the parallel frame members is a plurality of rollers, each of which rollers rotates about an axis perpendicular to the central longitudi- nal axis and parallel to the axes of other rollers among   the 45 plurality. The roller axes of the rollers supported by the support structure lie along a roller plane and, in a typical version, are spaced equally in accordance with a predeter- mined roller-axis spacing. At least one of the first and second ends of  the  support  structure  includes  a set of  extension 50 apparatus adapted for selective extension to, and  retention in, various positions in which the extension apparatus extends beyond the end of the support structure, thereby rendering the overall length of the support structure adjust- able. The extension apparatus is adapted for selective   cou-55 pling to, for example, a unit of equipment (e.g., another conveyor module) adjacent the conveyor module from which it depends. In a typical embodiment, each set of extension apparatus is infinitely positionable, and selectively retainable,  between  a fully retracted  and  a fully extended 60 position. That is, the extension apparatus can be selectively retained in any position of an infinite number of positions along a continuum between the fully retracted and extended positions.