Nested Gaskets
Presscut Industries die cuts a complete set of gaskets for a dc motor speed-control in one operation. This nested gasket set concept is a result of working closely with the customer to reduce piece-part price by producing the complete gasket set in a single operation with minimal labor and material waste. The set is die cut from 0.125-inch thick, open-cell-polyurethane foam, with a pressure sensitive adhesive on one side to aid installation. Typical production capacity for this type of part is over 2,500 parts per hour with inexpensive steel-rule die tooling. This type of die-cut part finds use in other applications such as medical, communications, appliances, and electronic items.
Greg Watson, Presscut Industries, 2908 Commodore Dr., Carrollton, TX 75007; Tel: (972) 389-0615; Fax: (972) 245-2488; E-mail: info@presscut.com.
Fatigue Machine
High-cycle fatigue (HCF), so-called because it appears after millions of repetitive cycles of use, can affect even high-strength metals such as the titanium alloys used in the gas turbines that power aircraft. The HCF tester combines a high-frequency actuator with a scanning electron microscope (SEM) to help engineers understand HCF in metals, a potentially catastrophic phenomenon in aircraft engines. Designed to fit within a scanning electron microscope, the machine takes advantage of its depth of field and high resolution. The HCF testing machine applies steady stress that simulates turbine component rotation using hydraulic pressure, while applying high-frequency dynamic stresses using piezoceramic plates that resonate at 1,000 to 1,700 Hz. Static loads up to 6,000 lbs and dynamic loads up to 1,220 lbs can be applied to the specimen.
Deborah Stowitts, Southwest Research Institute, P.O. Drawer 28510, San Antonio, TX 78228-0510; Tel: (210) 522-2046; Fax: (210) 522-3547. For more information, circle 574
Hydraulic torque coupler
Since torque capacity is critical in high-performance turbomachinery, heavy interference keyless fits are regularly used to join shafts. Called hydraulic fit, the technique is commonly used to mount components such as coupling hubs and wheels to machine shafts, and entails costly machining of matched precision tapers on both the shaft and mating component. Additional requirements include hydraulic pumps (low and high pressure) for mounting the hub on the shaft, and shims for axial adjustment. Mechanically actuated shaft coupling alternatives exist, but require tedious tightening of multiple screws and don’t provide as much clamping force. A patent pending hydraulic torque coupler (HTC) combines the best of both worlds. It provides secure clamping through simplified slip-fit com- ponents. HTC does not require heat, keys, splines, tapered shafts, or plug/ring gauges to install or use. Moreover, it offers axial and rotational adjustment within a specified range, simplifying machine assembly. HTC consists of three major components: a piston ring, a matching cylinder ring, and an inner ring with two inclined planes that provide the uniform force necessary to securely join a shaft and hub. Installation involves slipping the HTC over the shaft and hub, applying hydraulic pressure to the coupler, tightening six allen head set screws, then releasing the pressure. This process uses a single low-pressure hydraulic pump to deform the inner ring that squeezes the equipment hub, locking it onto the shaft. Setscrews mechanically hold it in position, allowing the oil to be drained. Mechanical retention eliminates loss of clamping and unbalance due to leakage.
Tim Lashinger, Riverhawk Co., 5152 Commercial Dr. East, Yorkville, NY 13495; Tel: (315) 768-1848; Fax: (315) 768-4941; E-mail:
tim. lashinger@ riverhawk.com.
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