Involute spline C-Hook or VBS

[Simtech]

To all!

 

A customer of mine is looking for a way to rapidely create external and internal involute splines according to the standard DIN 5480.

 

Does anyone know if this is available?

 

Thanks!

 

Luc

[mayday]

have you tried the gear c-hook or am I off base here

[Guest CNC Apps Guy 1]

I think this is a perfect candidate for a C-Hook. Dialog box to just put in the values and BAM out comes your spline(s).

 

On second thought, is the Create, Next Menu, Spiral/Helix detailed enough for that involute? Or the Fplot C-Hook shoudl be able to define that as well.

 

Here's the fplot doc.

 

code:

---

C-Hook Name: fplot.dll/txt

 

Date: July 18, 1997

 

Programmer: CNC Software, Inc.

 

Simple demonstration:

 

From the fplot main menu, select "Get eqn", then enter "sine.eqn" as the

file name. Select "Plot it" to create line segments that comprise one cycle

of a sine wave. Press Alt-F1 to fit the line segments to the screen.

 

Description:

 

Fplot is a function plotting program. It draws equations and optionally

creates corresponding geometry (points, lines, splines, NURBS curves,

parametric surfaces or NURBS surfaces). The equations are entered with

ordinary algebraic notation. The following functions and constants are

available:

 

(x) Parentheses (highest precedence)

 

function (lower precedence)

 

-x Unary minus (lower precedence)

x ^ y Exponentiation

 

x * y Multiplication (lower precedence)

x / y Division

 

x + y Addition (lowest precedence)

x - y Subtraction

 

abs (x) Absolute value

sqrt (x) Square root

sin (x) Sine

cos (x) Cosine

tan (x) Tangent

asin (x) Arc sine

acos (x) Arc cosine

atan (x) Arc tangent

exp (x) e^x

ln (x) Natural log

log (x) Log base 10

 

Predefined variables

 

pi 3.141592653589793

e 2.718281828459045

 

Main menu:

 

Edit eqn

Get eqn

Save eqn

Vars

Angle D/R

Origin

Geometry

Plot it

Trace Y/N

 

Edit eqn:

 

Allows the user to enter or edit a multi-line equation.

 

Get eqn:

 

Reads equations from a file (default extension is .eqn)

 

Save eqn:

 

Writes equations to a file.

 

Vars:

 

Defines one or two variables (one if Geometry is set to Draw Only,

Points, Lines, Splines or NURBS curve; two if Geometry is set to

any Surface option).

 

FPLOT: Variable definition

Var name

L. limit

U. limit

Step size

 

or

 

FPLOT: Variable definition

Var name 1

L. limit 1

U. limit 1

Step size1

 

Var name 2

L. limit 2

U. limit 2

Step size2

 

Angle:

 

Toggles between degrees and radians.

 

Origin:

 

Defines a point that is added to the curve or surface.

 

Geometry:

 

FPLOT: Geometry type

Draw

Points

Lines

Spline

Nurbs curve

Draw surf

Pts surf

Param surf

Nurbs surf

 

Plot it:

 

Evaluate equations and draw or create appropriate geometry.

 

Trace:

 

If trace is enabled, the equation, display parameters and variable

values are written to fplot.log and displayed after Plot it is selected.

 

Sample equations:

 

y = x^2 Parabola

 

x = y^2

 

z = x^3 Cubic

 

x = cos(t) Helix

y = sin(t)

z = t

 

x = 2.0 * cos(t) Ellipse

y = sin(t)

 

 

Reading formulas from a file: Ex:

 

angles = degrees / radians

 

geometry = draw

points

lines

spline

nurbs

draw_surf

points_surf

parametric_surf

nurbs_surf

 

step_var1 = t1

step_size1 = 0.1

lower_limit1 = 0.0

upper_limit1 = 5.0

 

step_var2 = t2

step_size2 = 0.1

lower_limit2 = 0.0

upper_limit2 = 5.0

 

origin = 0, 0, 0

 

The following samples files are included with fplot:

 

candy.eqn A surface that resembles a piece of wrapped candy.

cossurf.eqn A surface: z = cos(x^2 + y^2)

drain.eqn A surface that resembles a drain.

chip.eqn A surface that resembles a potato chip.

ellipsd.eqn An ellipsoid.

invol.eqn An involute curve.

sine.eqn A sine curve: y = sin(x)

tube.eqn A tubular surface.

 

Distributor: CNC Software

344 Merrow Road

Tolland, CT 06084-9970

 

Contact: CNC Software

Phone: (860) 875-5006

---

HTH

[Bullines]

There aren't any spline creation functions available to VBS. Not yet, anyway. C-Hooks, yes, though.

[Nominal]

What's wrong with using the create->next menu->add in's-> gear ?

[Simtech]

Thanks James, I was thinking in this direction but then I starting looking on the web for a shareware that would output the DXF file or some other type of file.

 

What would be really slick is to be able to tie in a dialog box with the FPLOT function ... imagine just punching in the numbers and voila, out comes the resulting geometry.

 

I've got the basic formulas from the Machinery's Handbook but for now just looking at possible different "read cheap" solutions.

 

Thanks!

 

Luc

[Jimmy Wakeford from Barefoot CNC]

Luc

If you know the numbers you want maybe a vb app to create an mc macro would work. Can you send me some info?

[John Summers]

GEAR.DLL should do it unless you have some really peculiar requirements. If you do, let me know. Involute splines are really stubby gears. You just change the OD and root diameter, and maybe the circular tooth thickness.

[Jimmy Wakeford from Barefoot CNC]

John I was down at J norris's place yesterday looking at his weird belt thread deal.

 

Seems like ther should be a formula for that.

[Simtech]

Here's the technical info:

 

Tolerance Class: 10h

Number of teeth: 22

Module: 1.0

Pressure Angle: 30 deg.

Base Diameter: 19.053 REF

Pitch diameter: 22.000 REF

Major Diameter: 23.8 h11

Form Diameter: 21.94/23.86

Minor diameter: 21.6 h14

 

Circular tooth thickness:

- Max Effective: 2.090

- min. Actual: 2.135

Measurement over 2 pins: 26.502/26.571

Pin diameter: 2.250 REF

 

Fillet radius: 0.16 min.

[Günther Massimo - GMCCS]

Google for KissSoft.

[John Summers]

Simtech,

GEAR.DLL should work just fine. The involute curves are found from pitch diameter and number of teeth, and of course, pressure angle. Enter OD and ID from your data. Enter the roll diameter and measurement over 2 pins, and the tooth thickness should come out to your spec.

In GEAR.DLL, don't forget to hit ENTER after each numerical entry. Just going to the next entry doesn't force the calculations.