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

The post Spring-like discs now in 250-mm dia. appeared first on Windpower Engineering & Development.

Boker’s Inc.
www.Bokers.com

The post Chemically resistant washers and spacers appeared first on Windpower Engineering & Development.

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

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