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Constant Force Extension Springs From SDP/SI

Press Release  |  July 15, 2013  |  New Hyde Park, NY

Constant Force Extension Springs From SDP Offer High Stress and Long Deflection

Constant force springs from Stock Drive Products are designed to be used in any application that requires a smooth, even, uniform load through the entire length of travel (deflection) for retracting or extending. They are used to counterbalance windows, doors, display racks and trays. They are also used in magazine feed drivers in vending machines and assembly line machinery.

Identified as the A 3X50-... Neg'ator® series, they offer high stress and long deflection. These are significant advantages over conventional coiled springs when used in applications where low or zero gradient is desired, limited space is a factor, large extensions are required, or high initial force at initial deflection is desired. The springs feature widths from 3/16" to 2", are made of 301 stainless steel for superior performance in harsh environments, and have at least one punched hole in the free end for fastening purposes. The maximum recommended load per spring ranges from .23 lbf to 40.9 lbf.

SDP/SI is a leading manufacturer of small mechanical components, servicing a wide variety of aerospace, medical and commercial industries for over 50 years. Quotes, online orders, and 3D CAD Models are available on our updated estore at SDP/SI offers over 130,000 small mechanical components, including gears, belt and chain drives, shafts, shaft accessories, bearings, couplings, universal joints, vibration mounts, miscellaneous components, hardware, gearheads and speed reducers, right angle drives, brakes and clutches, motors and gearmotors. For additional information about SDP/SI please visit

Stock Drive Products / Sterling Instrument (SDP/SI), 2101 Jericho Turnpike, P.O. Box 5416, New Hyde Park, NY 11042-5416. Phone: 1-800-819-8900 | 516-328-3300 • Fax: 516-326-8827.