Re: Re: Re: valve extensions or other remedies


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Posted by Rick Denney on August 17, 2001 at 09:32:10:

In Reply to: Re: Re: valve extensions or other remedies posted by Greg Crider on August 17, 2001 at 07:17:18:

To me, it's a question of minimizing evils. But first, some simple force analysis:

If the finger button and stem are stiff enough (and they are), then pressing an off-center button should impart no lateral force on the valve. But the motion must be straight down, exactly parallel to the axis of the piston, and this is true even if the finger is centered on the piston.

What causes lateral force on the valve and the ills you mention are when we don't push the buttons straight down. And why would we not? Usually it's because our finger doesn't rest properly on the button, and we end up pushing on the edge of the button rather than squarely on the top.

Consequently, I'll take an offset button that, because it is offset, can be pushed straight down, over a button that is just out of reach and therefore gets pushed on the edge of the button with a lateral component to the force. Conn rightly had this in mind with the offset buttons on short-action valves.

And I agree that I wonder what sort of people are in the minds of the designers. My York Master's fourth valve is nearly out of reach for me, and I have huge hands. I have also been considering possible solutions.

Rick "who can palm a basketball" Denney


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