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Flat Springs can take on a multitude of forms, from a simple leaf spring which operates in a single plane (as in a switch, for example) to a complex clip action which may operate in several planes at the same time.

Emmotts has built an enviable reputation in this field; which is amply demonstrated by their market share. The extensive range of standard tooling which Emmotts maintains often means their specialist tooling is not required for short run work . In conjunction with this , Emmotts has an `in-house' tooling facility to ensure the economical production  of high volume work. Materials range from mild a stainless steel, through to copper and nicol alloys

DESIGN CONSIDERATIONS

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= Load

= Young's Modulus

= Deflection

= Strip Width

= Material Thickness

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= Active Length of Spring

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Load Calculation

W = Efbt3

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4L3

CASE STUDY ONE

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CONSIDERATIONS

Environment within which the spring will be required to operate, eg - corrosive, electrical contact, temperature.

Detailed examination of how the spring will be required to operate, with particular reference to position of any active loading.

Particular consideration should be given as to whether the spring will be statically or dynamically loaded and levels of finish required, eg - edge de-burring, shot peening.

Sharp corners which may create areas of stress concentration, should generally be avoided.

Hole or slot sizes in material , particularly the moving parts of the spring and in the anchorage areas, should be considered carefully.                                                                                        

APPLICATION- A range of ceiling lamps for domestic and commercial use, including ornamental shaped glass designs. Designs are continually changed and updated to meet the trends and demands of a highly competitive market.

PROBLEM- This type of light fitting had previously been held in place by means of three screws. However this system limited the scope for new designs as decorative bezels could not be incorporated without drilling unattractive holes. An alternative means of fastening was needed which would be both versatile and easier to use.

SOLUTION- George Emmott designed and produced a tempered steel retainer spring which would clip onto the outer edge of the glass shade. This was then further developed to fit inside the rim so that it can be used in conjunction with any shape of shade within any given rim size. George Emmott continues continues to develop new fasteners to meet the  varied requirements of the lighting industry

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George Emmott (Pawsons) Ltd, Wadsworth Mill, Oxenhope, Keighley, West Yorkshire, BD22 9NE. Tel : 01535 643733; Fax: 01535 642108

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