An above ground frame pool is disclosed including a frame assembly and a liner supported by the frame assembly. The frame assembly includes a plurality of horizontal pipes, a plurality of vertical pipes, and a plurality of T-shaped joints. The joints may lack mechanical fasteners with adjacent pipes or corresponding apertures. The joints may be one-piece or multi-piece structures. Such joints may be water-resistant and convenient to manufacture, assemble, disassemble, and store.

Solar trackers that may be advantageously employed on sloped and/or variable terrain to rotate solar panels to track motion of the sun across the sky include bearing assemblies and other mechanical features configured to address mechanical challenges posed by the sloped and/or variable terrain that might otherwise prevent or complicate use of solar trackers on such terrain.

Solar trackers that may be advantageously employed on sloped and/or variable terrain to rotate solar panels to track motion of the sun across the sky include bearing assemblies and other mechanical features configured to address mechanical challenges posed by the sloped and/or variable terrain that might otherwise prevent or complicate use of solar trackers on such terrain.

Solar trackers that may be advantageously employed on sloped and/or variable terrain to rotate solar panels to track motion of the sun across the sky include bearing assemblies and other mechanical features configured to address mechanical challenges posed by the sloped and/or variable terrain that might otherwise prevent or complicate use of solar trackers on such terrain.

Solar trackers that may be advantageously employed on sloped and/or variable terrain to rotate solar panels to track motion of the sun across the sky include bearing assemblies and other mechanical features configured to address mechanical challenges posed by the sloped and/or variable terrain that might otherwise prevent or complicate use of solar trackers on such terrain.

Solar trackers that may be advantageously employed on sloped and/or variable terrain to rotate solar panels to track motion of the sun across the sky include bearing assemblies and other mechanical features configured to address mechanical challenges posed by the sloped and/or variable terrain that might otherwise prevent or complicate use of solar trackers on such terrain.

Solar trackers that may be advantageously employed on sloped and/or variable terrain to rotate solar panels to track motion of the sun across the sky include bearing assemblies and other mechanical features configured to address mechanical challenges posed by the sloped and/or variable terrain that might otherwise prevent or complicate use of solar trackers on such terrain.

Solar trackers that may be advantageously employed on sloped and/or variable terrain to rotate solar panels to track motion of the sun across the sky include bearing assemblies and other mechanical features configured to address mechanical challenges posed by the sloped and/or variable terrain that might otherwise prevent or complicate use of solar trackers on such terrain.

The disclosure concerns a coupling assembly comprising at least first coupler, a second coupler, locators which assist in properly aligning the couplers, and hardware to hold the two couplers together. The coupling assembly may have more than one coupler. One end of each coupler is configured to attach to an assembly member. Another end of each coupler is configured with a coupling mechanism such that it may be coupled to the coupling mechanism of another coupler.

The interior side of each coupling mechanism may have one or more recesses called locator pockets. The locator pockets on one coupler are configured to line up with the locator pockets on another coupler. As the first and second couplers are brought into an aligned position, a locator may be placed into the void created by each aligned locator pocket pair. After the locators are inserted and the couplers are brought into approximate alignment, the user may insert bolts through the couplers and apply nuts to the bolts.

The user may then tighten the nuts onto the bolts which will pull the interior sides of the two couplers towards each other. As the interior sides are pulled towards each other the locator pockets begin to apply a compressive force to the locators. This compressive force seats the locators into their respective locator pockets, causing the couplers to self-align, often colinearly, with each other. When the hardware has been firmly tightened, the locators will have accurately and precisely aligned the couplers with each other and helped to constrain the couplers longitudinally, vertically, and horizontally with respect to each other.

A system and method of calibrating a laser tracker is provided. The system includes a support system for quickly and easily moving an artifact to a desired position and orientation and for holding the artifact in the position and orientation. An adjustable alignment mirror is coupled to a first end of the artifact so that the more accurate ranging system of the laser tracker can be isolated to determine a reference length of the artifact. Additional measurements are then taken to exercise one or more error source within the tracker. The support system includes a positioner and a support beam for positioning and supporting the artifact. The artifact is coupled to the support beam using kinematic clamps that are designed to reduce or eliminate errors associated with over-constraining the artifact. The artifact is movable between a deployed configuration for use and a stowable configuration for ease of storage and transportation.