Guide Pulley System [GPS] The purpose of the guide pulley system is to guide the wire from the dancer pulley system to the guide rollers. Two of these systems exist: on both sides of the machine. The pulley bracket can be manually adjusted to line up with the appropriate grooves on the guide rollers. The guide pulley system is located in the space associated with the guide roller system. This is a very simple system with only four main parts. It must only meet a few engineering and customer requirements. A COMSOL model demonstrates that the system is subject to minimal displacement under extreme loading conditions. Stress levels are also within allowable limits.
Guide Pulley Rod [GPS201] The guide pulley rod is a hollow steel square extrusion with a half inch width. This rod holds the rest of the guide pulley assembly and attaches directly to the frame associated with the guide roller system. This extrusion can be commonly found at hardware stores, specifically Home Depot. A standard length of three feet from Home Depot (PRT#: 40290) is sufficient for both guide pulley systems. Additionally, a standard shaft collar from McMaster fits this extrusion perfectly. The rod would need to be cut to length and possibly coated for resistance against slurry. As shown in the overall finite element force analysis, the rod is able to withstand maximum stress and displacement forces.
Guide Pulley Collar [GPS202] The guide pulley collar clamps to the guide pulley rod and is attached to the guide pulley bracket. The two halves are separable, allowing the collar to be adjusted along the length of the rod so that the wire coming off of the guide pulley aligns with the correct groove on the guide rollers. This is a slightly modified standard part from McMaster. It meets the customer requirement of allowing for an adjustable position for the guide pulley. A standard shaft collar (PRT#: 3325K15) will be purchased from McMaster and the following modifications will be made: Re-tap existing holes with M6x1 threading Increase bores sizes to 0.43 inches in diameter Drill two holes in two parts as shown in drawing and tap with M6x1 thread The modified part meets all customer and engineering requirements. Adjustable screws are in metric units as requested. Stress and displacement levels are within allowable limits.
Guide Pulley Bracket [GPS203] The guide pulley bracket attaches to the guide pulley collar and holds the pulley assembly. The bracket is designed to position the pulley symmetrically to distribute the tensile load evenly and to ensure that the adjustable cap screws are easily accessible. This is a simple part, but it is designed with ease of manufacture and usability in mind. The slotted sections allow for the entire bracket to be removed and for the collar to be adjusted easily. With the pulley hanging below the rod, both the cap screws and the pulley are conveniently accessible for observation and adjustment. The part is designed to be cut out of a sheet of steel using a water jet, CNC router or laser cutter and bent to shape. A recommended bend radius is included for the specified sheet thickness. This part is the most at risk when it comes to stress and displacement under tensile forces. However, the finite element analysis shows values that are not unreasonable. It is possible to modify this part by increasing the thickness to ensure durability.
Guide Pulley Cap Screws [GPS001] This standard part allows the position of guide pulley collar to be adjusted. It also attaches the guide pulley bracket to guide pulley collar. According to customer requirements, it is adjustable using standard metric hex key. A standard M6x1 cap screw is nearly perfectly equivalent to a ¼-28 cap screw. The guide pulley collar is a standard part from McMaster with tapped holes for ¼-28 cap screws. Standard M6x1 cap screw will be purchased. No modifications are necessary. Physical tests of over tapping ¼-28 thread with M6x1 thread proved to be successful. A half inch thick block of steel was used.