Pulleys and Cable
|Ideal or not, sometimes access to a room is limited to the doorway. In other cases access is closer to the shades but still not within arms reach. Pulleys can be used with high-test steel cable to raise and lower a shade from a distance. In the case where pulleys are required to endure heavy loads, the use of several pulleys can allow a mechanical advantage, reducing the force required to lever the shade.
Pulleys must be chosen with an appropriate cable to avoid the cable becoming nested between the pulley wheel and it’s bracket. Static pulleys, as opposed to swiveling pulleys, reduce the likelihood of cable nesting, but this also generally fixes the location where the grower will be levering from. In instances as described above where a board is used as a manifold for several shades, mechanical advantage is required – use basic mechanical physics to ensure the load is manageable. In circumstances where several independent shades each have their own pulley and cable, wire cable clamps can attach several cables together so the height of the shades can be adjusted simultaneously.
|If one 1000W lamp can cover 4×4 then a shade moving back and forth on a 6′ rail can let the same lamp cover a 4×8? Not quite, unless you get creative. Imagine a series of rails placed around 4′ from each other, all parallel and running north/south. Every odd-numbered shade is started on the north end and the even-numbered shades are started on the south end. If the railed motors are all plugged in simultaneously on a power bar, then you have some improvement to light coverage. Is it going to perform as good as a static 1000W over a 4×4? Not in this cowboy’s opinion – but sometimes we have more space than we do power.|
Another creative use of the rail is for stadium rooms, where the plants are on a tiered platform – similar to gym bleachers or stadium seating. In this system bulbs often hang vertically between two “bleachers” (or a semi-rectangle) and the floor space is only a narrow walkway for access. A rail is then mounted above the walkway, with pulleys a few inches away on either end. Lamp hangers on either side of the rail (steel cable preferably) can then be attached to the rail motor through the pulleys, and as the motor travels along the 6′ rail each lamp will move up or down, in opposition. One lamp then can also be hung on the motor itself, with a static height, traveling back and forth with the rail. Perfect? I don’t think so.. but if you have a space that is 12 feet long and 5 wide you might have a higher yield with a technique similar to this.
Remember that the more complex you make a design, the greater the chance of an unforeseen problem arising. Don’t over-burden yourself with fancy equipment you do not need – keep your room as simple as it can be. If you can access your shades easily, use a well fastened chain system or whatever equally reliable device you prefer. Measure safety over novelty, and function over convenience, and you are well on your way to having a successful urban garden.