GearHeads Corner

Hi Art

I'm sure in real power driven systems spoking of a bevel gear is probably not desirable  from a strength point of view.  My world of tower clocks and chronometers the amount of force is not as much of a concern although weight (in the case of a chonometer) or material (tower clock).

Attached is a photo of a  "snail" that controls the number of strikes in an E Howard Tower Clock.  The snail is backed up with a contrate wheel that has spokes.  In previous research, it seems that a "contrate", "crown" and bevel gear all refer to the same type of gear as referred to in different applications.  Operationally a pin on a bar follows the snail as it rotates synched with the our hand. The outer most step would result in one strike and the innermost 12 strikes of the bell.

The attached SnailExample.gth file is zipped to decrease it in size and illustrates my first attempt to add a "snail" to the Tower Clock simulation that I'm putting together.

The attached Snail-2L.dxf & Snail-2R.dxf files are my first attempts to create the snail as an indicator that can be attached to a shaft. 

Bill

Hi Bill:

  Unfortunately, spokes cant be done on hem as a matter of how their constructed.
For your purposes though, there is a work around.. like so much in GM..
  Select the bevel and while its selected set the shaft diameter to 120 or so, then press respoke.

  Your bevel now has a giant hole in it, now make a circular gear with spokes with an outside
diameter equal to the hole size. Then place it on the shaft on top of the bevel. Right click it and select "Strip teeth"
, you now have a bevel with spokes.. only good for display.. but should work. :)

Art

Hi Art

Thanks,  I like that solution since I'm going for simulation look rather than actually creating such a large bevel.  I hadn't thought of that option.

Bill