Editorials
Renewegy Wind Turbines
Renewegy, LLC is a privately held USA based manufacturer of state of the art, electronically controlled wind turbines. Renewegy has brought big turbine technology to light commercial markets such as farms, businesses, schools and municipalities, allowing these markets to enjoy the same renewable energy that utilities have been harnessing for years.
In development of the high efficiency 20 kw variable pitch turbines, Renewegy Egineers encountered a fretting and corrosion problem with one of the bearings in the generator. The 100 mm OD bearing had a preload and needed to float in its iron housing in an environment that saw a good deal of vibration contributed to the fretting and corrosion. A solution was required that retained and centered the bearing outer ring and kept it from spinning while at the same time provided an axial retention low enough to allow the bearing to float. Such a solution was offered by USA Tolerance Rings.
Tolerance Rings go big for Nicholson Forest Product
Tolerance Rings are normally a few inches in
diameter and are used to join cylindrical parts.
Then came a request from Nicholson Forest Products Equipment Group, Sidney, British Columbia to help mount a thin section bearing in their debarking machine. Nicholson is a world leader in providing machinery for the log processing industry capable of handing logs up to 44 inches in diameter.
The bearing mount application required a ring that would be measured in feet not inches. The answer was to provide Nicholson with 150-ft coils, of custom high quality spring steel corrugated strip. They could then create a custom sized ring. The ring would measure from two to four feet in diameter as required for their bearing sizes.
The Tolerance Ring allows for wider tolerance ranges as well as compensating for a minor out-of-roundness before the bearing is clamped into position. During operation, it allows for thermal growth between the bearing and housing as the logs speed though the debarking process. The tolerance ring also acts as an aid in absorbing vibration.
Mounting Magnets
Tolerance Rings, which are fasteners that act as elastic shims, provide many design advantages. The unique wave, formed into the stainless steel strip, provides a force to hold the magnets firmly but gently in place.
The configuration of the Tolerance Ring can be adjusted to accommodate the many design constraints providing a spring rate strong enough to hold over a large tolerance range yet soft enough to prevent damage to the magnet material.
Today's devices are made of various materials to make them lightweight, quiet, or even snap together. These materials have different rates of thermal expansion and are exposed to a large range of temperature in storage and operation. Automotive under hood temperatures range form -40F to 350F and higher, causing a massive range of stress on the sensing components. With a direct press fit the magnet material becomes the weak link and can be damaged or the magnet holder can become loose, compromising position control. Glue joints can soften or become brittle as a result of temperature and time, resulting in system failure.
On the other hand, a USA Tolerance Ring's natural spring range allows for the differences in thermal expansion, countering the long term effects of creep and cold flow with softer plastic housing materials.
Dexter Washer and Dryers
Dexter Laundry, Inc. of Fairfield, Iowa started in 1894 as a manufacturer of wringer washing machines. Today, it is a 100% employee-owned national and international industry leader in the commercial laundry market along with the Industrial and On Plant Laundry sectors.
Dexter offers a full line of coin and debit card operated washers, starting with the T- 30 Model and going up to the T-1200 model, with a load capacity of 80 pounds of dry clothes. These front-loading washers have a horizontal final drive shaft supporting the perforated basket, that holds the clothes. This shaft is driven by a belt pulley, which originally employed a woodruff key to secure the hub to the shaft.
Over time, Dexter engineering felt that the keyway could weaken the hub, thereby introducing unwanted backlash during the reverse action cycle; where the tub goes forward for 12 seconds, pauses for 3, and reverses for 12, typically repeating this cycle for about 18 minutes or longer. To eliminate the risk of both slippage and backlash, USA Tolerance Rings were introduced to secure the hub on all the units up through the 50 pound T-750 Model. These keyless torque devices are also used on the Dexter dryers.
USA TOLERANCE RINGS
85 Route 31 North, Pennington, New Jersey 08534
phone:609-745-5000; fax:609-745-5012