Tool Sets

[Vikas]

Being born as an engineer (!!) I just don't see how dual pawl could make the clicks per revolution double :-(

I can see only one way of doing that but it will make the ratchet prone to slip. For example, if the pawl teeth are half sized than the wheel teeth but that would be poor design engineering.

- Vikas

 

[stephen9666]

Originally Posted By: Vikas
Being born as an engineer (!!) I just don't see how dual pawl could make the clicks per revolution double :-(

I can see only one way of doing that but it will make the ratchet prone to slip. For example, if the pawl teeth are half sized than the wheel teeth but that would be poor design engineering.

- Vikas


Some ratchets use a design where the pawls trade off being engaged, as a way to double the number of clicks per revolution. I don't know if the Wright uses this design.

So, here's an example of how it could work.

Pawl 1 is engaged with the teeth in the head of the ratchet. Pawl 2 is sitting in between two teeth. The ratchet begins to rotate. Pawl 2 engages the next tooth and pawl 1 is now sitting between two teeth. This trade off continues as the ratchet rotates.

 

[ajchien]

Originally Posted By: Vikas
Being born as an engineer (!!) I just don't see how dual pawl could make the clicks per revolution double :-(

I can see only one way of doing that but it will make the ratchet prone to slip. For example, if the pawl teeth are half sized than the wheel teeth but that would be poor design engineering.

- Vikas


Originally Posted By: Vikas
Being born as an engineer (!!) I just don't see how dual pawl could make the clicks per revolution double :-(

I can see only one way of doing that but it will make the ratchet prone to slip. For example, if the pawl teeth are half sized than the wheel teeth but that would be poor design engineering.

- Vikas


There are many different dual pawl designs, for round and pear shaped heads.

Just open up a few of your ratchets.

The prime example is probably snap on's dual 80. However, dual pawls go way back, I believe that Williams? might be credited with the first dual pawl design in a round head maybe in the 1950s or even before.

The dual pawl ratchets I have include Willams B52, Williams S52, Williams S53, Bonney T502K, really old SK 42470, Craftsman RHFT (Easco relabel), and a newer Crescent.

I'd take a guess that the HF composite ratchet is also dual pawl just by the looks of it. Actually, i think most ratchets over 40 tooth are dual pawl.

 

[ajchien]

From alloy artifacts website:
---------------


S-52 1/2-Drive Dual-Pawl Ratchet

In 1951 W.J. Johnson filed a patent for an improved fine-tooth ratchet design, and the resulting model S-52 (and related) ratchets became highly successful products for J.H. Williams. In this next figure we'll look at a very early example of the S-52 ratchet and discuss the patent behind it.


Fig. 322. Williams S-52 1/2-Drive Dual-Pawl Fine-Tooth Ratchet, with Insets for Side View and Reverse, ca. 1951-1956.
Fig. 322 shows an early example of the Williams S-52 1/2-drive ratchet, with "S-52 Superratchet" and "Pat. Pend." forged into the handle, and with "J.H. Williams & Co. U.S.A." forged into the reverse.

The overall length is 11.2 inches, and the finish is polished chrome.

The patent pending notice corresponds to patent #2,772,763, filed by W.J. Johnson in 1951 and issued in 1956. The patent describes a ratchet mechanism with a dual-pawl progressive advance design, closely based on an earlier patent #2,395,681 by W.H. Odlum et al of Duro Metal Products.

The key to the patent is the use of dual pawls with an odd number of gear teeth, so that the pawls are always a half step out of synchronization. This allows the ratchet to get another "bite" with only half the angular displacement, effectively doubling the gear pitch.

 

[ajchien]

Originally Posted By: stephen9666
Originally Posted By: Vikas
Being born as an engineer (!!) I just don't see how dual pawl could make the clicks per revolution double :-(

I can see only one way of doing that but it will make the ratchet prone to slip. For example, if the pawl teeth are half sized than the wheel teeth but that would be poor design engineering.

- Vikas


Some ratchets use a design where the pawls trade off being engaged, as a way to double the number of clicks per revolution. I don't know if the Wright uses this design.

So, here's an example of how it could work.

Pawl 1 is engaged with the teeth in the head of the ratchet. Pawl 2 is sitting in between two teeth. The ratchet begins to rotate. Pawl 2 engages the next tooth and pawl 1 is now sitting between two teeth. This trade off continues as the ratchet rotates.


Yeah, you can even hear and feel two different pawls click in most dual pawl ratchets.

 

[Roadking]

Just for the record...
I did buy the $59 Stanley Black Chrome…it was the 150 piece (or so) set. Being a mechanical designer by default (having all my common sense and imagination logic intact) I’m interested in fit, finish and function. The black chrome finish is top notch and the laser etched lettering is easy to read. The ratchet(s) indexing is precise and smooth.
The only down side I can see is looking for a black socket in a dark environment. Wonder if I could spray the tops with some day-glo bright paint? I think I’m going to buy myself a set and try that.

 

[Vikas]

I have the HF composite but I do not think that is user serviceable so I do not think I can open it.

Your patent numbers are great help. I will print and look at them. When it says "odd number", are they talking about teeth count on the pawl or on the wheel.

- Vikas

 

[punisher]

Originally Posted By: Roadking
The only down side I can see is looking for a black socket in a dark environment. Wonder if I could spray the tops with some day-glo bright paint? I think I’m going to buy myself a set and try that.


I remember long ago buying a set of Snap-on black handled screwdrivers because they looked "cool'. Couple weeks later I bought another set of black handle screwdrivers from Snap-on, reminding myself to be more careful about where I left them. Month later I lost most of those. Later on I bought some bright yellow or lime green dayglo Matcos and never had another problem losing them, except for a rather careless helper who managed to lose about $500 of tools during the short time he worked for me.

 

[ajchien]

Originally Posted By: Vikas
I have the HF composite but I do not think that is user serviceable so I do not think I can open it.

Your patent numbers are great help. I will print and look at them. When it says "odd number", are they talking about teeth count on the pawl or on the wheel.

- Vikas


http://www.garagejournal.com/forum/showthread.php?t=88511&page=3

In the above link, post #56, someone has opened and taken pictures of the HF composite dual "tick tock" pawl mechanism. its a nice thread showing the innards of a lot of ratchets. My 3/8 Crescent (Taiwan) from Costco has nearly identical insides to the HF composite. I think the "tick tock" dual pawls is seen in a lot of pear head shaped ratchets.

 

[mjoekingz28]

Originally Posted By: JGunn
Irwin is another good example. I swear by genuine Vice Grip products. guess what? made in china. great stuff, too! Love all the Irwin products, some of the best mid range tap and die and drill bit sets you can get for the money.. although the tap and die stuff is actually manufactured in the USA still.



These companies are catching on to use not buying their Chinese items. Now, alot of them say "Made in China to Irwin's strict specifications" or some wording similar.

 

[bob15]

The companies are also saying "Made in PRC" or people's republic of china.


bob