                         HELICAL ROUND WIRE SPRINGS        HEP9.HLP

    Enter  only that  data that  is pertinent.   After you  see your  first
    results you can adjust your input to meet your requirements.

    Your  first  concern in  designing  a  spring  is  the type  of  spring
    required,  a  compression  spring  or  an  extension  spring.   With  a
    compression spring the  load compresses the spring.  The  spring in its
    free state has  a gap between its  coils and is at  its longest length.
    An extension in its  free state has no gap between its  coils and is at
    its shortest length.  The load stretches the spring to a longer length.

    The type  of service  expected from your  spring is  a factor  that can
    affect the  design.  When possible it  is better to design  your spring
    for  sever  service  as  springs  have   a  habit  of  being  used  for
    applications other  than what  they were  designed for.   The following
    discusses the meaning of types of service:

    Sever Service:
    Springs subjected to  high speed deflections for  extended time periods
    and  through  a  large  percentage   of  their  range.   For  1,000,000
    deflections or more.

    Average Service:
    Springs that  do not exceed 18,000  deflections per hour and  uses less
    than  75 per  cent of  the spring's  range.  For  100,000 to  1,000,000
    deflections.

    Light Service:
    Springs subjected to  small deflections and infrequent  use.  Less than
    100,000 deflections.

    If the diameter of  your spring is important, it must fit  in a hole or
    it  must fit  over a  rod, then  enter a  diameter.  You  can enter  an
    outside diameter, an inside diameter or  a mean diameter.  You may want
    to let the program select a diameter  on the first pass and then change
    it to some nominal value.

    The program will select  a wire diameter if you do  not enter one.  You
    will be asked to  enter a wire diameter after the  program has computed
    one so that you can enter a standard size.

    You may select a  material from the material list or  you may enter the
    modulus of elasticity for some other material if you so desire.  If you
    enter the modulus of elasticity you will be asked to enter an allowable
    working stress.

    The overall length  of the spring depends  on the type of  end applied.
    The lengths  in the program  refer to  the active coils  and allowances
    must be made for type of ends on the spring.

    For compression springs you may enter a  working load and the length at
    which that load applies.   You may also enter a spring  rate,  the load
    in pounds per  inch of deflection.  Or  you can enter two  loads at two
    different lengths.   If you have entered  a spring diameter and  a wire
    diameter then you can enter an extended length and the number of active
    coils.  This may be valuable when checking an existing spring.

    For extension springs  you may enter a  working load and the  length at
    which that load  applies or you may  enter a working load  and a spring
    rate.  Extension  springs often have  an initial load  when compressed.
    You can enter  this load or let  the program set the  initial load.  If
    you want an initial load of zero then enter "0".  If you have entered a
    spring diameter  and a wire  diameter then  you can enter  a compressed
    length and  the initial load.   This may  be valuable when  checking an
    existing spring.










