Walking beams

Just to satisfy my curiosity, can our American friends tell us why they call beam engines "walking beam engines? Adding the prefix "walking" seems to imply that there are also non-walking beams.

Maurice

Maurice, in the UK, "walking beams" are a set of two pairs or more (usually) of beams arranged a bit like the parallel links on a steam engine wheels. As one pair goes up the other pair go down and if you place something across them, as they go up and down in sequence the item will "walk" along the beams. That is a lot easier to understand if you see it rather than try and describe it with words!

Mark

Having read that again, I suspect you are aware of our understanding and I cannot help with the American reasoning...

Edited By Mark C on 19/06/2014 23:20:06

I just found this bit of video that is rather nice..  http://www.youtube.com/watch?v=759kPVhJKvk 

Edited By Mark C on 19/06/2014 23:24:14

John, I think I misunderstood the original question (as noted in the edit).

I know nothing of the names for steam engines - stationary or otherwise, I only know about walking beam mechanism in industrial applications. They are commonly called walking beams and often used in transfer systems if you want to keep fixed intervals between parts. The model using balls is a good example as the balls drop into a detent to keep them under control. They are sometimes used in furnace feeders as they can be made from ceramic beams and you do not get wear as the parts move along, they are akin to "pick and place" without the complications.

Mark

Discussed here on MEM with a few replies from the US

Apart from various flying control linkages vis Chinook cyclic / collective - two rods in parallel connected at each end by a common pivot to allow the rods to move both together (fore and aft) and independently (one forward, one aft). whilst maintaining synchronisation, were referred to as walking beams by our American cousins at Boeings.

I always considered that the 'Walking beam Engine' was one on which the supporting column was pivotted at its base to allow for the motion of the beam if a watts linkage wasn't used.

.

John,

According to this Patent it's a Walking Beam Drive Apparatus

MichaelG.

Edited By Michael Gilligan on 20/06/2014 09:43:13

John,

Yes, walking beam as I said earlier and identified by Michael. They come in a number of variations but they all produced an intermittent "walking" or "stepping" movement.

Mark

John,

Sorry for confusing matters, I originally misunderstood the question and went off in the wrong direction!

Mark

On some early US patents the connecting rod is called a Pitman. Possibly derived from a saw pit, one man at the top and one in a pit sawing logs? Only my guess, anyone know?

Don't know that one either but I can tell you that the git of a power press that does the pressing (on the end of the crank connecting rod) is called a "pitman"

Mark

Possibly because when ships had beam engines installed, the beam and some of the mechanism was above deck level.

Viewed from the side that could give the impression of the beam mechanism "walking".

Edited By V8Eng on 20/06/2014 19:18:38

I'm not sure how much it helps, but this short paper [from MIT] illustrates both the Walking Beam and Pitman Arms, on a "Sucker Rod Pump".

Digging around t'internet, it appears that a Pitman is generally a rod or lever fixed to some rotating item, so as to produce approximately linear motion. [Steering Arms, etc.] ... although at least one Dictionary states it to be just another term for a Connecting Rod.] ... I remain confused!

MichaelG.

Just within topic this subject reminded me of many years back when I went to work in a steel works one of my first jobs was to assist in the breakdown repair of what was termed 'walking beam' it moved red hot steel bars down the cooling bed, much like the one in the video and I have to say I was fascinated by them and would often when passing just stop and watch them for a few minutes all those steel bars marching along with military precision !