Author Topic: Douglas Patents of Note 04  (Read 6365 times)

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Offline Doug

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Douglas Patents of Note 04
« on: 27 Oct 2007 at 01:36 »

Improvements in or Relating to Valve-operating Mechanism for Internal-combustion Engines and the Like.

Patents of Note 04
Patent No.: 127,146
Application: Jul. 13, 1918
Complete: Jan. 11, 1919
Accepted: May 29, 1919

Stephen Leslie Bailey and William Wilson Douglas (Willie) paired up for this unusual and interesting cam arrangement.  It seems to be an attempt at the ‘one shaft does all’, as well as avoiding the expense of bevel gearing by using simpler to manufacture skew gears.  It specifically states the design is suited to where the valves are parallel to the axis of the cylinder.  Cam follower fingers (D) accommodate the necessary cylinder offset with the camshaft (C).  This would have meant reorienting the parallel, but inclined valve stems of the venerable 2-3/4hp.  It was not adopted, possibly because of concerns over wear from the small diameter of the skew gears in proportion to the load they would carry.  It would be seven years before they altered the valve gear arrangement with the new EW model, and that would adopt a different arrangement.  The whole cam/tappet unit is mounted on a detachable plate (E), which is also part of the claim. 

Douglas thought enough of the design to also patent it in the United States of America; one of the rare occasions that they did so.  In fact the accompanying illustration is from the US patent, the corresponding British patent omits Figure 2 where the full glory and complexity of the design is on display.  Items (T, S, R, & R2) are part of an exhaust valve lifter mechanism described in the body of the patent though not in the claims.  In the British patent in the absence of Figure 2 the mechanism is only sketchily described.  Though the wording is slightly different the claims of both patents are identical.  I have never seen an engine like this, but the patent illustration are in a rather advance state of detail, suggestive of quite a lot of developmental thought or of advancement to prototype stage.   

© 2007 D. Kephart, Glen Mills, PA, USA