Clock Escapements

[Michael1962]

Hi everyone,

Surfing and doing some reading to increase my knowledge a bit.

I have been reading the following chapters regarding recoil escapements. What is puzzling me though is in chapter 5 the point of the tooth on the escape wheel lead the root of the tooth. In chapter 6, the teeth are reversed and the root of the tooth leads the point of the tooth.

Is it meant to do that or am I missing something in the change between chapters?

The pallets are the same between chapters, but the escape wheel is a different configuration.

Any reply is appreciated.

[watchweasol]

Hi Michael   which book was it in, If other members have the same book they may be able to shed some light on it.

[Michael1962]

Oops. It is online. Forgot to post the link.

[Michael1962]

I think I have found out what is going on. I think the topic has shifted from the Graham escapement to a recoil escapement.

Happy to be told otherwise if I am off track.

[watchweasol]

http://demonstrations.wolfram.com/TheGrahamClockEscapement/  the attached link and video will help in understanding,  I found it a bit confusing until Chap 6 super imposed the two.

 

[Michael1962]

Thanks for that. I have been watching some of the videos from there as well.

I had pretty much worked out that the recoil escapement was named that as it reversed the escape wheel.

Something that I found confusing on the link that I have above is where they talk about the force arrows (vectors) and then said if they changed the pallet angle, then the impulse force would be only 38%. They showed no information as to where they got that number from. The graph later showed that, but when the comment was first made, there is nothing.

Just makes it a bit confusing.

Edited February 13, 2021 by Michael1962

[oldhippy]

The best way of watching the recoil is to look at a movement with a seconds hand you can clearly see the seconds hand drop back hand. Longcase clocks are good for that. 

If they changed the pallet angle the clock would not work correctly it would be either to shallow or to deep. 

Here is something to get your teeth into. I loved working on this type. 

 

 

[Willow]

never seen on escapement like that you can see why it's called a grasshopper love it

[watchweasol]

A clever piece of engineering , I believe the original was made from Lignum Vitae a hard wood .

[oldhippy]

It's the hardest wood you can get.  

[Joseph111]

If I remember correctly it is also quite oily and hence there is no need for extra lubrication.
I would love to have a go at building a grasshopper escapement but I think the deadbeat is complicated enough.

[Michael1962]

I understand the concept and how it works, but some of the names and numbers in the 'subtitles' I am not sure of.

Hopefully, this is all explained in the books that I am going to purchase, but haven't yet.

[watchweasol]

Hi Michael   A lot of the books discribe the escapements in different terms but as long as you have the concept in mind , The recoil, Deadbeat, etc you will be able to understand the language.  There are many designs but all do the same job and despite their different designs the working surfaces are more or less the same for the angle to give the impulse.

[rodabod]

Hi Michael, one tip I have is to master your understanding of the recoil escapement first, and then move onto the others. Otherwise it could become slightly confusing. 
 

The anchor/recoil is clever in many ways and fairly bomb-proof. The recoil phase acts like negative-feedback (if you are familiar with electronics) which is a bonus if you have spring drive with inconsistent power delivery. 
 

The Graham deadbeat is quite reminiscent of the lever escapement, except it is not a detached type (this is a very important distinction when looking at how to aim for isochronism). It’s very much like the recoil escapement, but with two distinct pallet faces where one supplies impulse and the other is the “dead” face which is cleverly shaped such that as it moves, the escape wheel remains static, and thus no recoil. 

[oldhippy]

You will find this interesting on the dead beat. For you it's best to look on the net because there is so much out there about clock escapements, far more than what we can tell you. 

https://demonstrations.wolfram.com/TheGrahamClockEscapement/