Lego Clock Escapement W12.3

Lego Clock Escapement W12.3
Galileo escapement (~1637) with a 12-teeth escapement wheel. Like W1, but with better defined and more easily adjustable contacts. Impulstransfer is approximately tangential (i.e. with minimal friction), but unlocking is radial. Friction between the lifting pin and the unlocking lever can be eliminated by making the lever rotating about the pendulum arbor. Although unlocking friction can be made small, it may be variable, as a result of irregularities in the gear train, thus disturbing the pendulum motion in an inpredictable way.
The weight, 70g, drops 1.25 mm/s.
For construction details of the escapewheel see W12.1
Like the chronometer escapement (Arnold,1780; Earnshaw,1781), unlocking and impulsing is only once in a period, leaving the pendulum free the rest of the time.
Unlike the chronometer escapement, unlocking and impulsing is at the end of the back swing, rather than in the middle of it.
See the lego chronometer escapement by horolophile.
See also W17.

Category:

Science & Technology

Tags:

• lego
• clock
• escapement
• chronometer
• detent

[BenVanDeWaal]

The length of this arm is dictated by (1) it should lock the scapewheel in the position that is most favourable for impulstransfer: scapewheelaxis, pendulumaxis and transferpoint approximately on a straigth line (tangential impulstransfer). (2) the locking face should be parallel to the tooth edge With the orientation and position of the arm so determined its lenght was only a matter of finding a suitable pivot hole in the frame.

[lolcat23]

@BenVanDeWaal I actually didnt write what i meant. What i meant was. since you have a little bit of free fall(escape wheel turning after impulse is done but before it hits the resting surface). So what i meant was "if you make the brake arm *longer*". But yes, like you said, the locking face should be parallel, and im used to being able to file those kind of surfaces so they are parallel - something you can not do with lego. so making the arm longer will make the impulse face on the wheel contd

[BenVanDeWaal]

@lolcat23 I see. I think a small free drop is always necessary with a radial impulstransfer to get space for the pallet to swing back (and come again). Radial impulsing gives least friction, provided you keep the contact as short as necessary to give just enough impuls. But you will know this all. Regards, Ben.

[BenVanDeWaal]

@lolcat23 Tangential I meant, not radial.

[lolcat23]

if you make the brake arm shorter. will you still get enough impulse? or are the increments to crude to make the adjustments?

Inspiring stuff, your escapements.

[BenVanDeWaal]

@lolcat23 (Contnd). The arm is nearly balanced, but, owing to is lenght, it has a relatively large moment of inertia. I can not see how the lenght could affect the impulstransfer. I hope I understood your question well. Thanks for your interest. Ben.

[geegeevindaloo]

Hi Ben, I loved this so much that I tried adapting the mechanism for one of my sculptures!

[lolcat23]

@lolcat23 contd. push the brake arm up. Its probably fixable by choosing another hole in the plate and changing the geometry of the brake arm. but thats a lot of hassle for a little problem :)

[BenVanDeWaal]

@nafativedec This is correct, provided the pendulum has the required length for a period (complete swing) of 1s.

[nafativedec]

Is this correct that I get 60 sec clock if I connect this pendulum to 8 tooth gear and than I connect this with 40 tooth gear.

It should be right? This pendulum has 12 tooths so it has to turn 5 times to get 60 ticks and 40 / 8 = 5 (40 tooth and 8 tooth gear).