<HTML><HEAD> <META http-equiv=Content-Type= content=text/html;charset=ISO-8859-1></HEAD> <BODY text=#000000 bgColor=#ffffff>Ric, You've really= blown it.  You now cannot take out a patent on your= idea...;-]   "if you publish a method before= patent filing, novelty is violated and you can get no= patent"  Bernie Or maybe this isn't considered= publishing? David I. <DIV style="PADDING-RIGHT: 5px; PADDING-LEFT: 5px;= PADDING-BOTTOM: 5px; BORDER-LEFT: #000000 3px solid;= PADDING-TOP: 5px"> <HR> Original message From: Ric Brekne= <RICBREK@BROADPARK.NO> To: pianotech= <PIANOTECH@PTG.ORG> Received: Sun, 17 Apr 2005 22:26:26= +0100 Subject: Capstans... which brings me back= to.... And update on my Magnetic Assist mechanism for the= grand action. The Virtual capstan of a couple years back that= btw has been  up and working just dandily this past year= now.  8 hours a day they are banging away on this= instrument.. But too the point.... I have not been= satisfied trying to deal with the standard capstan adjustment= when using the fold down magnet assembly.   So... I've= come up with a new version of the old rocker arm... which I= think has many good points. Note... The following = amounts to Public Disclosure of an invention. True to style any= one is free to open source develope the concept as they wish,= but no patents can follow unless one devises a clear improvement= on the basic idea. First a drawing of the rocker= arm. <IMG alt="" src="mhtml:file://C:\Documents and= Settings\David Ilvedson\Local= Settings\Temp\xPlus\60BD6977-0A6B-41EE-BBD2-EF5965EFBEF3.mht!cid= :part1.00020407.07040704@broadpark.no"> The assembly= features an axled roller (brass) instead of a standard capstan= for the interface with the whippen cushion. It is also axled to= the key (red dot on the half round in the middle) The magned= assembly is just behind that, and the height adjustment is in= the front.  It employs a lock nut on both the under and top= sides of the rocker arm.  This allows for precise adjusment= of the roller height with the use of only one screw instead of= the old two screw type. Further, only one screw is needed as the= assembly is held in place both by the front adjustment screw and= the center pinnning in the middle. All this allows for= complete freedom of adjustment of both  the  physical= <<capstan>> height (in the form of the roller) and= the virtual capstan height (magnet) The roller allows for= a minumum of friction between the key assembly and whippen= cushion. No sliding whatsoever. An article on this is in= the works and I expect to publish soon. The Magnetic Assist= Grand Action by Richard Brekne is an open source development= project and can be used to replace significant amounts of lead= in the keys.  Read the article in both the PTG Journal last= year and the European for more infomation. Cheers= Richard Brekne <PRE>A common misperception. = It does slide. The involute curve is the standard gear tooth profile. The important quality of the involute curve,= is that it transmits uniform angular velocity. So that as the driving= gear rotates at constant RPM, the driven gear also rotates at constant RPM,= with minimum noise and vibration. But they do slide. Make your self a paper= cutout and try it. It's also interesting to consider the angle of gear teeth. = Standard angles for spur gears are 14 and 20 degrees. 14 degree teeth are= smoother and quieter, and have a longer wear life because at a given load they= have lower contact stress. In fact, zero angle or negative angle= would be even better, from a contact stress point of view, but with small or= negative angles there is a geometry problem known as "undercutting", = where the base of the tooth ends up narrower than the contact area, and is prone= to fracture. 20 degree teeth are a compromise, used for pinions= with very few teeth to prevent undercutting. So does a capstain slide on the wippen cushion felt, except for= the instant that the contact point passes through the "magic line". Before= and afer that point, the Overs capstain slides the least, standard= vertical capstan slides a little more, and the Steinway backwards leaning capstan= slides a little more than that. more than you wanted to know, and it still does not explain why= S&S might have done that. Mike</PRE> </DIV></BODY></HTML>