While what's left of my right brain was in tick-over mode (idling for us in the US) dashpot popped into my consciousness. It seems a peculiar term, defined as a damper of vibration, shock, or unwanted energy. What are its origins? I've found nothing. A hyphenated version, dash-pot, appears to be a French/English blend meaning a melange of liquors, so not likely related. Can someone dash off a pot full or answers to its origins?

I've not heard of the word, Geoff. I did a little looking but couldn't find it. Sure wish I still had the OED. Does anyone?

I have always known the word as describing those hydraulic devices that close a door automatically and gently. I am sure it could also be used to describe any other similar damping device.

Wordweb defines it thus:

A mechanical damper; the vibrating part is attached to a piston that moves in a chamber filled with liquid

I know the definition - I seek the origin of the term. This may be another of those "origin unknown" words, but it didn't just pop out of thin air! RE, I'm surprised that you do not associate the term with the famous British S-U carburettors!
That's where I first learned of it.
https://www.google.com/search?...sAQ&biw=1440&bih=781

The OED says:

quote:

a contrivance for producing gradual descent in a piece of mechanism or for preventing vibration or sudden motion, consisting of a cylinder or chamber containing liquid in which a piston moves; a hydraulic buffer.

"a contrivance for producing gradual descent in a piece of mechanism" - not the best definition ever written.

quote:

Originally posted by Geoff:
I know the definition - I seek the origin of the term. This may be another of those "origin unknown" words, but it didn't just pop out of thin air! RE, I'm surprised that you do not associate the term with the famous British S-U carburettors!
That's where I first learned of it.
https://www.google.com/search?...sAQ&biw=1440&bih=781

I am familiar with SU carburetors and have one of them on my Wolseley Hornet and a pair of them on my Rolls-Royce. But I have never heard the damping chamber referred to as a dashpot. In fact, the chamber is filled with air, not oil, on an SU. There is a little oil in it to lubricate the mechanism but it's not a hydraulic damper as in a door-closer.

For us, a dashpot is an emergency crapper.

quote:

Originally posted by Richard English:

I am familiar with SU carburetors and have one of them on my Wolseley Hornet and a pair of them on my Rolls-Royce. But I have never heard the damping chamber referred to as a dashpot. In fact, the chamber is filled with air, not oil, on an SU. There is a little oil in it to lubricate the mechanism but it's not a hydraulic damper as in a door-closer.

Well I'll be damned! I guess all those BMC and British Leyland service schools I attended in my youth gave me incorrect information!

As I wrote, I have never heard the SU damping chamber referred to as a "dashpot". That is not to say that the late companies BMC and BL did not use this term.

But if the piston damper in an SU carburettor is correctly known as a dashpot, then the term refers to devices with similar (but slightly different) operational charateristics.

Interesting word this dashpot. The OED2 suggests that it is similar to other verb + noun constructions using dash, e.g., dash-buckler, dash-wheel, dashboard. The device itself was invented (and patented in 1842) by F E Sickels (later spelled Sickles) (link). Sickels describes his dashpot in the patent, but does not use the term:

quote:

I also claim the manner of regulating the closing of the valves, and of effectually preventing them from slamming, by means of a water reservoir, furnished With a piston, or plunger, attached at the lower end of the valve stem, and operating within an adjustable cup, or secondary reservoir, so as to effect the purpose intended, upon the principle, and substantially in the manner, herein described and made known.

The dashpot was use for a cut-off valve on a steam engine. It seems the patent was later infringed on by the manufacturer of another steam engine (the Corliss steam engine), and much litigation ensued. The device was being referred to as a dashpot at least within a decade or two of its invention. Much heat was generated by this simple device. Horatio Allen refused to use the Sickels cut-ff valves on his steam engines and got involved in litigation and finally in legislation when the whole mess was taken to the US Congress to allow Sickels' son to extend the patent past its 14 year limit.

Besides being used to allow doors to close slowly rather than slamming shut, dashpots were used in carburetors to slowly de-accelerate (to prevent stalling) when a driver let up suddenly on accelerator. If one searching using the terms dashpot and carburetor in Google Books, many instances will be found with illustrations in such periodicals as Popular Mechanics. It is sometimes called a throttle return check.

Excellent, z. I always appreciate analysis, rather than just links or quotes. I particularly find the patent infringement interesting.

The damper on an SU carburettor is not the same as a throttle return check - which is a dashpot in the sense that I know it.

The damper on an SU is there to stop flutter of the needle valve.

I always appreciate analysis, rather than just links or quotes.

You're welcome.

I particularly find the patent infringement interesting.

Here's a link to one of the legal docs I found: link.

quote:

This is remedied, in Sickels' apparatus, by constructing his dash-pot or reservoir, so that the plunger can move at some distance from the sides of the vessel at first, and the water thus pass freely up the sides, while, at the lower part, the reservoir is contracted, so that, when the plunger reaches it, the escape of the water will be diminished. In this way, the weight passes rapidly at first, till 81 it closes the valve, and is then checked by the increased resistance of the water, the great object being to permit the valve to cover its port as quickly as possible, and check it at the instant this result is attained.

This message has been edited. Last edited by: zmježd,

I came to this site because I was curious about the origin of the word "dashpot". The quote found by zmježd jarred something loose: "dash-pot or reservoir so the plunger can move". I recalled that an old fashioned word for the plunger that was used in a 19th century butter churn is "dasher". It moves up and down in a reservoir or "pot".

Here is an image of a butter churn of that sort:
http://printables.scholastic.c...-013_p01_286x316.jpg

and here is an image of a pretty standard looking modern "dashpot"
http://www.globalspec.com/Imag...a90710718cff24ae.gif

Those two images make it perfectly clear that "dashpot" is a portmanteau of "dasher" and "pot". The really interesting thing is how unobvious this is to 21st century readers. In the 19th century when this invention was first made, everybody knew about butter churns and the dashers that were used in them. No doubt to the people of that time, "dashpot" was as obvious in meaning, as a portmanteau of "interconnected network" would be to us.

Welcome to our humble abode, TYoke! We are a bit slow these days, but I am hoping things will pick up.

I am sure you are right about dashpot being clear in the 19th century, but a bit unclear to us. It's interesting how time affects words. Today's generation, for example, wouldn't understand the word "dial" for a phone, whereas those of us who are a little older of course do. There are many other examples like that, I am sure. What are others you can think of?

Good job, TYoke! Many thanks - and thanks for joining us!

Now I suppose I'd butter churn up some more discussions.

Yeah, we've been a bit slow lately, to say the least. Let's all do a little churning.

quote:

Originally posted by TYoke:
... "dashpot" is a portmanteau of "dasher" and "pot".

I have my doubts. A dasher agitates the cream to change it into butter, while a dashpot dampens motion to slow something down, an opposite action. I think dashpot is probably just a combination of dash (A sudden check; abashment; frustration; ruin, 5th definition) and pot. Dasher probably comes from a different meaning of dash, perhaps " to strike with violence so as to break into fragments; to break in pieces by a violent stroke or collision; to smash," from the OED.

Interesting take, Tinman. I think you make a good point about the opposite meanings, though, as we've discussed here before, there are words with opposite meanings.