Machined spring offers high accuracy

Citation

(2004), "Machined spring offers high accuracy", Aircraft Engineering and Aerospace Technology, Vol. 76 No. 6. https://doi.org/10.1108/aeat.2004.12776fad.003

Machined spring offers high accuracy

Machined spring offers high accuracy

Keywords: Precision engineering, Machining, Aerospace industry

Taylor Devices introduces its new line of machined springs, which are said to provide a highly precise, linear and repeatable spring element for precision equipment. Possible applications are aerospace, weapons systems and scientific instruments.

According to David Lee, Western Technical Director, “Taylor Devices' machined springs fulfill the need for absolutely precise, predictable springs that fit within a confined volume and remain exactly in line when they stroke. They do not tilt or rotate when exercised as do conventional springs”.

According to Taylor Devices, finite element analysis (FEA) enables spring rate and strength to be predicted accurately prior to fabrication with less than 1 per cent error. Subsequent honing can bring the spring rate to the exact desired amount within measurement error.

“As opposed to a helical configuration, the Taylor Devices machined spring features a cross slot configuration that allows us to provide the most accurate performance prediction available to the industry”, said Lee.

FEA also accurately predicts stresses at all points in the spring for a design that stays well within fatigue limits. Capable of achieving essentially infinite life, Taylor Devices machined springs feature inherently square ends and a one- piece construction that can include mounting flanges, attachment threads and other fittings. This allows the spring to be an integral part of the machine instead of an add-on.

Taylor Devices can fabricate these springs from a wide variety of materials, including high strength steel, stainless steel, aluminum, titanium and high strength plastics. These materials can deliver specialized features such as corrosion resistance or freedom from magnetic properties. The ultrahigh strength steel that is available can reduce weight by 50 per cent or more compared to springs made of conventional high strength materials, since spring weight is inversely proportional to the square of the allowable material stress.

“It is important to note that machined springs cost significantly more than a conventional coil spring”, said Lee. “But if extraordinary light weight, precise alignment, or exact and consistent spring rate is required, a machined spring should be carefully considered”.

Taylor Devices state that unlike coil springs – which require a special attachment to operate in tension – machined springs inherently permit both tension and compression operation through built- in attachments. Taylor Devices machined springs are claimed to be inherently linear because residual stresses are eliminated and the coils never rest against each other as the spring deflects. Spring rate is the same in both tension and compression.

The company also claims that while coil springs exhibit unavoidable low frequency resonances (surge), machined springs have much higher resonances that are less troublesome. In addition, Taylor utilizes a proprietary treatment to effectively damp out all resonances.

Details available from: Taylor Devices Inc. Tel: +1 716.694.0800; Fax: +1 716.695.6015; Web site: www.taylordevices.com