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Info Letter No. 43 (May/June 1997)

FED1+ Swedish Version

The FED1 software for pressure spring calculation is now also available in Swedish. It was decided at the "HEXAGON Kick-Off", one day seminar in April this year in Sweden, to translate the HEXAGON spring programs into Swedish for the Fj„der AB Stockholm branch and Lesj”fors AB sales personnel in Sweden, Norway, Finnland, Denmark and England. Fj„der in Stockholm have the exclusive sales right for the Swedish versions. If you are interested in a Swedish version of our spring programs, please contact Mr G”ran Eriksson at:

S-52400 Herrljunga
Tel. +46-513-23200
Fax +46-513-23021
E-Mail: Goran.Eriksson@lesjoeforsab.se

The manual has not yet been translated into Swedish. However, you can choose between a manual in German, English, French, Italian or Spanish.
You can down-load a Swedish demo version of FED1 from the Web:


In the near future we will also be providing a Portugese version of FED1+. Our sales partner, Mr Renato Penchel in Brasil is currently working on the Portugese version.

FED3+ Rectangular and oval wire

Torsion springs made of wire with rectangular or oval cross-sections can now be calculated with FED3+ (not FED3). In contrast to pressure and extension springs, the load on twist springs is not caused by torsion but by bending. For this reason the greatest stress does not occur at the outer thread of the weakest point, but at the point where the distance between the wire and mid-line bending direction is greatest. You can select either rectangular, elliptical or sqaure wire under "Edit->Calculation Method". Input of the width b, and height h, instead of wire diameter d, will be required during dimensioning.

FED3/FED3+ Guide bar/bush

The recommended diameter for guide bar and bush, in accordance with DIN, are included in the printout.

FED3/FED3+ Quick Input

Individual data can be changed in the Windows version under "Edit->Quick". All data is reset under "File->New" and the NULL file is loaded if it is available.

FED2/FED2+ Eye Form

The extension spring eye form can be selected in accordance with the description and drawing in DIN 2097. From version 7.5 and up, it is possible to define variations under "Other Eye Form". We assume use of an insert piece when calculating the wire length. The number of rolled coils is asked for (can also be set to zero).

FED1+ Command Line Mode

You can use the new FED1+ command line mode to use FED1+ purely as a calculation module in your own program, or for fast calculation of hundreds of pressure springs. FED1+ loads a file with input values, calculates the pressure spring, saves the results in a file, and then quits. The required results can then be taken from the EDI file and be further processed. The EDI file format is described in Chapter 15 of the manual. The command line mode is activated by starting the program with "FED1 filename /E".

FED2+ Preliminary Concept

Until now, the preliminary concept for extension springs calculated the best possible extension spring for use by entering d=0. The adjustment occurs via the eye length LH. For a very large LH value, FED2+ automatically converts to a hook-eye. Alternatively, now you can also enter the eye height, LH, from which the wire diameter d is calculated. Wire diameter and number of coils is then greater than really necessary, but this increases the safety margin or life expectancy and a standard eye can be used. Both diagrams show a preliminary concept for both methods. At the top, the eye length LH is variable (hook eye), at the bottom the wire diameter and number of coils is increased.

ZAR3 - Safety Margin Diagram

As for ZAR1+ and ZAR2, ZAR3 now also includes diagrams showing the curve for safety margins against root fatigue fracture and pitting in relation to rated torque.

WL1 - Student Version

We now have a cost-free student version of our shaft calculation program WL1. Both are available for down-loading on the Internet under http://www.hexagon.de/wl1s_d.zip. The student version is based on WL1 (minus roller bearing data base) and in contrast to the full version, is limited to 10 shaft segments (instead of 50), with 5 each shearing force, path loads, bending moments, axial force, stress concentration zones and torques. The student version may be used for education and training purposes only. Commercial use is strictly prohibited. The manual for the student version is included as a HTML file. The manual can be viewed or printed out with Netscape or Internet Explorer.

WL1+ Electronic Manual

A suggestion for our customers using WL1+ with a floating licence in a network: Make the manual available in the network or Intranet along with the program. The files can be down-loaded from "http://www.hexagon.de/zip/wl1shb_d.zip" on the Internet. The manual is available for the student version, for this reason the chapter on roller bearing calculation is not included. If this idea catches on, the manuals will be changed completely.

SR1 - Flange Nut

Metric flange nuts in accordance with ANSI are now included in the SR1 software for calculation of bolted joints. The data base file "FLANGENUT.DBF" includes the sizes from M5 to M20. The bearing surface is greater in comparison to hexagon head nuts in accordance with DIN 934. This reduces surface pressure, a washer is therefore not necessary.

WL1+ Torsional Rigidity

If you wish to calculate twist spring constants (rigidity) of a shaft (e.g. to calculate torsional fatigue of a drive rod), define any torque, with introduction at the beginning and exit at the end of the shaft. The rigidity is then obtained from the angle displacement calculated by WL1+.
     Torque T
R = ---------------------------
     Angle of displacement phi

Windows Programs: Copying via the clipboard

With all Windows programs you can use CTRL-C to copy the contents of the active window to the clipboard, then with ALT-V you can insert the contents of the clipboard into other Windows programs provided the hi-lited text has been previously marked. In this way you can use the Windows calculator to make conversions. Drawings and diagrams can be copied with the PrtScrn-Key (whole screen), or with ALT-PrtScrn (active window only) into the clipboard.

Windows Data Base

Until now you had to pay attention to the decimal comma or point when entering numerical values into the data base. It was important to use the decimal point and not the comman. In the new versions you can use either comma or point, the comma is automatically converted to a point. I would like to thank Mr Brutschin of Rotzler in Steinen for this suggestion.

Date Configuration

The type of date used in the printout can now be configured in the new versions. Three different date formats are available. The configuration can be altered under "File->Settings->Printer".

Printout of Headers

It is now possible to configure the number of empty lines when printing out the HEXAGON software results on company letterhead paper. However, this is only possible when enough space remains for the printout (dependent upon printer and Windows print-driver). The standard setting is zero (no empty lines).

ZAR2 - Auxiliary Picture

The auxiliary picture contains the most important formulae for calculation of safety margins against corrosion in our bevel gear program ZAR2.

DXFPLOT - Font Type

The font type PC-8 is used in our software DXFPLOT, HPGL-Manager and DXF-Manager for output on HPGL plotter or laser printer. This allows German, Swedish and French special characters to be printed. The font now used looks different to that used until now and is also slightly smaller. You may have to increase the text width factor in the settings under "CAD-TEXT" for DXFPLOT or in the DXFPLOT command line.

DXFPLOT Configuration

Under "File->Settings->DXFPLOT" you can configure up to five DXFPLOT command lines. By entering "0" the possible parameters such as scale, interface, displacement, etc. will have to be entered. Then the command line will be generated. DXFPLOT now also requires input of the DOS or Windows version. The Windows version is called "WDXFPLOT.EXE", all other parameters are the same.

French Demo Versions on the Internet

The programs FED1+, FED2+, FED3+, FED5, FED6, FED7 and DXFPLOT have been available in French for some time. We have recently added French brochures to the World Wide Web. French demo versions can also be down-loaded and orders placed. I would like to thank Isabelle Vignat from Limours in France for her good work at HEXAGON during her apprenticeship in training for "Foreign Language Secretary".

Hardcopy under Windows

Users converting from DOS to the Windows versions often miss the ALT-P key combination for printing out graphics. The hardcopy function is also available in Windows, however not with ALT-P but in the menu under "File->Print".

Mailbox 03693-478319

If down-loading of demo versions from the Internet takes too long for you, you can dial into our Mailboxes via ISDN or Modem and then down-load the demos. The transmission rate for ISDN is approximately 6 kB/s. This means a demo version of HEXAGON software can be down-loaded in less than one minute. You can access the HEXAGON mailbox 07021-480015 via Modem (2,400 to 28,000 bps) as well as via ISDN adapter with 64,000 bps (X.75). We now have a new Mailbox with the number 03693-478319 (ISDN or analoge). The mailbox computer is in HEXAGON's new branch in Meiningen (Thringen, East Germany). A seminar with demonstration of HEXAGON software is planned there in the autumn for customers and interested parties in east, central and northern Germany. Please let us know if you are interested in taking part.

WN1 - Safety against permanent deformation

The WN1 software for pressed fit calculations includes, among other things, the calculation for safety SPA against plastic deformation. Now WN1 can also calculate elastic-formed pressed fits with overstrain of up to 30% of the hub volume in accordance with DIN 7190. In such a case, SPA is smaller than one because (non-damaging) overstrain occurs. A new factor, SPAx=pPA/p has been added which defines the safety against full overstrain of the outer part. SPAx must always be greater than one, although SPA < 1.0 only shows the transition from a pure elastic fit and an elastic formed fit.

Windows - Window Size

In the Windows vesions you can set the window size under "File->Settings->Graphic". If the diagram is to fill the whole window then accept the resolution shown in the header. If the boarder (set under printer configuration) is not shown on the right-hand side or lower boarder, configure a few pixels less, e.g. 1024x765. If the lower portion of the picture is hidden by the Windows 95 start bar, you can either pull this to the right with the left-hand mouse button, or you can configure a few points less, e.g. 1024x720.


Under the Windows program settings for "Printer" or "Graphic" you can configure whether or not the drawing or diagram should have a border.