Spring-like discs now in 250-mm dia.
October 5, 2011 by Paul Dvorak
Filed under Bearings, Mechanical Components, Wind Power News
One application for disc springs is to preload bearings.
Disc Springs look like conically-shaped washers, a shape that lets them take an axial load. They can be used individually or assembled into stacks for a required deflection. Spirol Disc Springs’ performance characteristics are predictable, letting designers calculate a minimum life cycle. They also provide high levels of load/force in a small space, unlike other springs which require a significantly larger footprint to carry the same load. Their predictability, high reliability, and unparalleled fatigue life make the disc springs preferred over other types of springs in critical applications such as safety valves, clutch and brake mechanisms for elevators and heavy equipment, and supports for industrial pipe systems.
The two major updates to the newly expanded product line are larger sizes per DIN 2093 Group 2 (now available up to 250-mm dia.), as well as a full range of stainless steel Discs. Details are provided in the updated Disc Spring design guide.
The company’s Application Engineering team can assist with a best method of stacking the discs for the required force-deflection characteristic when multiple Disc Springs are required.
Spirol International Corp.
www.spirol.com
Chemically resistant washers and spacers
May 10, 2011 by Windpower Engineering
Filed under Editorial, Mechanical Components, Turbine Design
Washers and spacers are available in a variety of chemically resistant materials. Many harsh environments require washers to withstand a various chemicals and abrasive, corrosive, high purity, or viscous fluids. Many materials may be suitable depending on the specific chemical, temperature, and application. These chemically resistant products provide manufacturers with quick access to washers and spacers fit for a specific applications. ODs range from 0.08 to 5.140 in., and washers and spacers are available in a broad range of inside diameters and thicknesses.
Boker’s Inc.
www.Bokers.com
Tower bolting technology improved with interlocking cam fasteners
Greg White
Vice President
DISC-LOCK International
Culver City, Calif.
www.disc-lock.com
Wind-turbine towers appear to be rising to new heights–literally. As blade lengths increase to capture more wind energy, towers must also reach higher to accommodate the longer blades.
Increased tower dimensions also translate into elevated levels of vibration and stress on tower fasteners, which can lead to loosening and bolted-joint failure. However, fastener failure can be eliminated with a locking washer.
Locking washers come in pairs with cam faces glued together.
The working principle behind the device is simple: It consists of two washer-shaped pieces that are preassembled (glued pairs), and have inclined cams on one side with a series of radial ridges on the other. On installation, the two cam sides are mated together and placed between the nut and joint material. Under vibration, the nut attempts to rotate loose. But because the cam angle is greater than the bolt-thread-pitch angle, the interlocking cams and non-slip ridges of the washer work together. The resulting jamming effect prevents loosening and further locks the assembly, thereby maintaining joint integrity. The result: a vibration proof fastening system.
Locking washers from DISC-LOCK have a steeper cam angle than the angle on bolt threads. Hence, vibration cannot turn them loose.
The locking washers also offer a fastening system that combines a heavy hex nut and tension-control bolt. Tension-control bolts are replacing conventional high-strength, friction-grip bolts and swaged-collar rivets because they are quick and easy to install with a lightweight electric shear wrench. Guaranteed tension and a visual inspection eliminates the likelihood of operator error and ensures engineers that connections are tightened in accordance with specifications. This bolting system is easily removed and can be reused. Other types of secure bolts are not reusable because they must be burned or cut off for removal, thus destroying the bolt.
The bolt spline works with the electric shear wrench.
The electrically powered shear wrench is lighter than hydraulic wrenches, a distinct advantage when considering tower height and precarious installations. This translates to a one-man operation that trims installation cost. The DISC-LOCK shear wrench uses an outer socket to engage the nut, while an inner socket engages the bolt. The two sockets rotate in opposite directions allowing the nut to turn while the bolt remains stationary. This counter-force operation transfers no torque to the operator, thereby reducing fatigue that can cause carpal tunnel syndrome.
Other interlocking cam fasteners from the company can help maintain bolted-joint integrity on wind farms. These include hex-head bolts for use in blind-hole applications and locking nuts that can be installed with standard tools. Forces that induce other lock nuts to loosen cause locking cam nuts to tighten.
Two sockets on the electric shear wrench work in opposite directions, turning the nut to turn while holding the bolt stationary. Zero torque to the crew member means less stress and fatigue on him.
WPE
Free washer catalog shows 24,000 nonstandard possibilities
November 5, 2009 by Paul Dvorak
Filed under Fastening-Joining for Wind Power, Materials, Mechanical Components
A 2010 Washer Catalog features an increased selection of 24,000 non-standard flat washer and spacer sizes available without tooling charges. The complimentary catalog from Boker’s Inc, Minneapolis, provides easy reference to available washers and spacers, which include ODs from 0.08 to 5.140 in. as well as many IDs and thicknesses. The catalog offers near endless washer and spacer possibilities with immediate access to more than 2,000 commonly specified and difficult-to-find material variations.
Materials listed in Boker’s 2010 Washer Catalog include low-carbon sheet steel, various spring steels, stainless steel, aluminum, brass, copper and nickel silver. Non-metallic options include ABS, acetal, polyester, nylon, MD nylon, polycarbonate, fiber, polyethylene and various phenolics. Tools for non-metallic materials are listed in boldface for easy reference.
The company maintains an ISO 9001:2008 registered status, ensuring accuracy and efficiency in all manufacturing processes. Boker’s Inc is a Woman Owned, ISO 9001:2008 registered manufacturer of high quality stampings and non-standard washers and spacers. Request a copy at (800) 927-4377.
Free 2010 scheduling calendar sports metric conversion chart
October 9, 2009 by Paul Dvorak
Filed under Mechanical Components
A 2010 scheduling calendar and metric conversion chart is available free from Boker’s Inc, a Minneapolis-based manufacturer of stampings and non-standard washers and spacers. The 2010 calendar serves as a one-page scheduling tool—complete with an easy-to-use metric conversion chart on the back.
The calendar spans 15 months, with Sundays and holidays conveniently marked in red. Also, the handy metric conversion chart includes the decimal and millimeter equivalents for common measurements, including 1/64 to 1 inch, plus inch equivalents for measurements from .1 to 100 mm.
The company has over 24,000 flat non-standard washer sizes without tooling charge and 2,000 material options, including low carbon steel sheet, various spring steels, stainless steel, aluminum, brass, copper, and nickel silver. Non-metallic materials such as ABS, acetal, polyester, nylon and PTFE are also available—providing millions of washer possibilities.
To receive the calendar and conversion chart, pick here then select the Scheduling Calendar box, and supply the requested information.
